Polymer, process and composition

ABSTRACT

There is described a low number average molecular weight (M N &lt;10 kD) and high glass transition temperature (&gt;75° C.) copolymer (optionally a solid grade oligomer (SGO)) that comprises (a) at least 20 wt-% of itaconate functional monomer(s), (b) not more than 40% of a hydrophilic monomer, preferably an acid functional monomer(s) in an amount sufficient to achieve an acid value from 65 to 325 mg KOH per g of solid polymer; (c) optionally not more than 70% of other monomers not being either (a) or (b), having a max content of vinyl aromatic monomer(s) of 40 wt-% and/or max content of methacrylate(s) of 40 wt-%; where the weight percentages of monomers (a), (b) and (c) are calculated as a proportion of the total amount of monomers in the copolymer being 100%.

This invention relates to polymers made from itaconate and similarmonomers; to a process for making these polymers and to their use incoatings, inks and adhesives.

Itaconate esters, also known as 2 methylidenebutanedioate esters, aremonomers that can be obtained from biorenewable sources. Yet despitebeen well known for many years, they have not been widely used to makecommercial polymers because they often are expensive and difficult toprocess.

Polymers with a low molecular weight (low Mn) and a high glasstransition temperature (high Tg) are desirable for several reasons. Theycan form useful coatings, may be used as stabilizers (e.g. in emulsionpolymerization). They may produce films with improved hardness andblocking resistance. Examples of such low Mn, high Tg polymers are solidgrade oligomers (also referred to as SGO).

The applicant has found that itaconate esters can be used to prepareimproved polymers such as low Mw/high Tg solid grade oligomers.Surprisingly the various difficulties of using itaconate ester monomerscan be overcome and they may be incorporated into polymers having someor all of the advantages described herein. Itaconate polymers of theinvention may also form films at room temperature which are highlyflexible (elastic) and are less prone to blocking.

As used herein the term solid grade oligomer (SGO) preferably denotes anoligomer composition comprising an oligomer (preferably the oligomerhaving a weight average molecular weight as measured by GPC of no morethan 100,000 g/mol) the composition substantially comprising solidmaterial (preferably solid in an amount greater than or equal to 95% byweight of oligomer composition, more preferably consists of solidmaterial) under standard conditions. The terms “oligomer”,“substantially comprises” and “standard conditions” are defined later inthis document,

Polymers prepared by bulk polymerisation of methacrylate monomers aregenerally poorly converted or require undesirable process conditions. Ina further problem addressed by this invention the applicant has alsofound that these methacrylate monomers can be wholly or partiallyreplaced by itaconate or similar monomers. This can reduce theconcentration of initiators and/or lower the polymerisation temperaturesrequired to produce polymers. The resultant polymers are prepared at ahigh conversion rate of monomer and have similar properties to thosemade from the methacrylate monomers.

The further optional problem is addressed by the invention. It has alsobeen found that omitting styrene monomers results in several undesirablechanges to the polymerization process especially when producing lowmolecular weight polymers. For example initiator concentration isincreased, chain transfer agent (CTA) is used and/or polymerizationtemperature is increased. Vinyl aromatic monomers such as styrene arealso undesirable for other reasons as they are possible carcinogens andhave other potentially chronic adverse health effects. It would bepreferable to use as little vinyl aromatic monomer as possible andpreferably omit these monomers entirely. Styrene monomers havepreviously been replaced with methacrylate monomers (for example asdescribed in EP156170). However as described above there are problemswith using methacrylate monomers as a direct styrene replacement. Theapplicant has unexpectedly found that itaconate functional monomers canbe used to replace vinyl aromatic monomers such as styrene (in whole orin part) to achieve similar properties to those imparted by suchmonomers in the resultant polymer. As used herein unless the contextdictates otherwise ‘styrene’ (e.g. styrene-free) may also refer to anysimilar vinyl aromatic monomers.

Thus to summarise one aspect of the invention the applicant has nowsurprisingly found that itaconate ester monomers can be used to replaceor reduce the amount of styrene and/or methacrylate (MA) monomers addedto a polymer whilst addressing some or all of the consequent problemswith low-styrene, low-MA, styrene-free and/or MA-free polymers. Thus (inone aspect of the invention) low M_(w)/high Tg polymers can be preparedwith low water sensitivity at a much reduced (or even zero) styreneand/or MA content at a reasonable monomer conversion using lower amountsof chain transfer agent (CTA), lower initiator concentrations and/orlower temperatures then before.

For example one preferred object of the present invention is to providepolymers having a number average molecular weight of less than 15kg/mole and Tg greater than 75° C. that are substantially free of vinylaromatic monomers. Such polymers may be prepared using no more than 1weight part (per 100 monomer) of CTA, less than 1 mole parts (per 100monomer) of initiator and/or from a polymerisation at a temperature ofno more than 275° C.

Further problems that may also be addressed by the present invention aredescribed herein and it is an object of the present invention to solvesome or all of the problems identified herein.

Some of the prior art documents are discussed below.

WO82/02387 (SCJ) describes a bulk polymerization process for preparinglow molecular weight vinyl polymers having a dispersion index less than2 and a number average molecular weight from 1000 to 6000. The polymersare prepared by continuously charging a mixture of at least one monoalkenyl aromatic monomer and at least one acrylic monomer into a reactorcontaining a molten resin mixture of unreacted monomers and the vinylpolymers at a temperature from 235° C. to 310° C., whilst maintaining aflow rate so the residence time of the monomer in the reactor is 2minutes and the reaction mix is kept at a predetermined level.

EP156170 (SCJ) describes a similar bulk polymerization process to thatdescribed above for preparing enhanced yields of high solids, lowmolecular weight acrylic polymers having a narrow molecular weightdistribution and a low chromophore content. The process involvescontinuously charging mixture of a polymerization initiator and at leastone acrylic monomer (in respective molar ratio of 0.0005:1 to 0.06:1)and a reaction solvent (in amount of 0 to 25% by weight % of the acrylicmonomer) into a reactor containing a molten mixture of unreacted acrylicmonomers and the acrylic polymer whilst maintaining a flow rate so theresidence time of the monomer in the reactor is >=1 minute, the reactionmix is kept at a predetermined level and the molten resin mixture iskeep at an elevated reaction temperature sufficient to provideaccelerated conversion to a readily processable, uniform, concentratedpolymer product.

EP554783 (BASF) describes a process for the continuous polymerization ofvinyl monomers to form vinyl polymers by free radical initiated orthermally initiated polymerization within an annular gap reactorcomprising an outer tube and a cylindrical rotor inserted therein so theannular gap is 0.5 to 10 mm wide, giving a residence period of from 1 to10 minutes. The outer tube is temperature controlled so thepolymerization is performed at 150 to 270° C. providing a vinyl polymerhaving a molecular weight Mn of from 1000 to 20,000 and a polydispersity(Mw/Mn)<3.5.

U.S. Pat. No. 6,346,590 describes a continuous polymerization andcondensation process of continuously charging into a primary reactor amixture of: at least one radically-polymerisable monomer with aradically polymerisable group and also a condensation reactivefunctionality (CRF); at least one modifying agent (not a monohydroxyalcohol) having a group that reacts with the CRF; where the temperaturein the primary reactor is kept at a level to polymerize the monomereffectively and to allow at least a portion of the CRF to react with themodifying agent to produce a gel-free first polymer incorporating atleast some of the modifying agent. The radically-polymerisable monomeris being added to primary reactor as the first polymer is beingsimultaneously removed. The first polymer is added to a secondaryreactor maintained at an effective temperature to form a second polymer.

WO2005/097854 (DSM) describes an aqueous composition comprising: i) atleast a cross-linkable vinyl oligomer A with a weight average molecularweight in the range of from 1000 to 80,000 g/mole obtained by bulkpolymerisation of: (a) 5 to 45 wt % of vinyl monomers bearing ionic orpotentially ionic water-dispersing groups; (b) 0 to 30 wt % of vinylmonomers bearing non-ionic water-dispersing groups; (c) 2 to 25 wt % ofvinyl monomers bearing cross-linkable groups; (d) 0 to 40 wt % ofa-methyl styrene; (e) 10 to 93 wt % of vinyl monomers not in (a), (b),(c) or (d); where (a)+(b)+(c)+(d)+(e)=100%; and ii) at least a vinylpolymer B with a weight average molecular weight >5000 g/mole, obtainedby polymerisation in the presence of vinyl oligomer A of: (f) 0 to 5 wt% of vinyl monomers bearing ionic or potentially ionic water-dispersinggroups; (g) 0 to 20 wt % of vinyl monomers bearing non-ionicwater-dispersing groups; (h) 0 to 15 wt % of vinyl monomers bearingcross-linkable groups; (i) 60 to 100 wt % of vinyl monomers not in (f),(g) or (h); where (f)+(g)+(h)+(i)=100%; where the ratio of vinyloligomer A to vinyl polymer B is in the range of from 5:95 to 95:5;where polymer B is more hydrophobic than vinyl oligomer A; where theweight average molecular weight of vinyl polymer B is more than theweight average molecular weight of vinyl oligomer A; iii) 0 to 20 wt %of co-solvent; and iv) 30 to 90 wt % of water; wherei)+ii)+iii)+iv)=100%.

Further prior art documents describe the use of itaconate esters ingeneral terms.

U.S. Pat. No. 4,206,292 (Kureha Kagaku Kogyo Kabushiki Kaisha) describesa vinyl chloride resin composition having surface smoothness comprises:(1) 100 parts of vinyl chloride polymer; and (2) 0.1 to 30 parts of apolymer processing aid comprising: (A) 10 to 100 parts of a copolymercomprising 20 to 99% of an alkyl methacrylate, 1 to 70% of a dialkylitaconate, and 0 to 60% of a copolymerisable monomer; and (B) 0 to 90parts of a copolymer comprising 80 to 100% of an alkyl methacrylate, and0 to 20% of a copolymerisable monomer. This vinyl chloride resincomposition is not very relevant for coating compositions to be preparedfrom bio-based or other environmentally benign sources.

U.S. Pat. No. 4,547,428 (Monsanto) describes a terpolymer comprisingrepeating units derived from an olefin, a diester of an additionpolymerisable unsaturated dicarboxylic acid, and a solubilizing monomerwhich promotes compatibility between the terpolymer and a vinyl halidepolymer. A granular form of the processing aid and a method for itspreparation are also disclosed. These polymers are not suitable forcoating applications.

U.S. Pat. No. 4,588,776 (Monsanto) describes a polymer compositioncomprising a blend of a vinyl halide polymer and a particulateterpolymer having a molecular weight of at least 100,000 and a glasstransition temperature of at least 50° C. The terpolymer comprisesrepeating units derived from an olefin, a diester of an additionpolymerisable unsaturated dicarboxylic acid, and a solubilizing monomerwhich promotes compatibility of the terpolymer with the vinyl halidepolymer. These polymers are used to prepare shaped plastic articles andnot for coating applications.

U.S. Pat. No. 6,951,909 (3M) describes a polymerisable system comprisesan organoborane, at least one polymerisable monomer, and a work-lifeextending agent.

WO11/073,417 (DSM) discloses an aqueous emulsion comprising at least avinyl polymer, said vinyl polymer comprising: a) 45 to 99 wt-% ofitaconate ester monomers having formula (I), wherein R and R′ areindependently an alkyl or an aryl group; b) 0.1 to 15 wt-% of ionic orpotentially ionic unsaturated monomers; c) 0 to 54 wt-% of unsaturatedmonomers, different from a) and b); and 0.9 to 54.9 wt-% by weight oftotal monomers of a chaser monomer composition added subsequently andpolymerised after the polymerisation of monomers a), b) and c); whereina)+b)+c) and the chaser monomer composition add up to 100 wt-%; andwherein the aqueous emulsion contains less than 0.5 wt-% free itaconateester monomers of formula I based on the total weight of the aqueousemulsion. Although it is a stated object of the invention to provide avinyl polymer with a high total concentration of itaconate estermonomers (see page 2, lines 14 to 17) in practise the larger proportionof such itaconate esters are lower itaconate esters (i.e. esters ofsmall alkyl groups such as DMI). This document does not teach that itwould be desirable to use a high concentration of higher itaconateesters (i.e. esters of large alkyl groups such as DBI). Indeed '417states that itaonate esters are difficult to process (see page 2, lines23 to 25) which combined with the teaching of the examples demotivates areader to incorporated large amounts of hydrophobic higher itaconateesters like DBI in a copolymer. The only examples in '417 that describeuse of a DBI monomer are Examples 2, 4, 5 and 6. It can be seen that DBIis used as co-monomer only at a low concentrations in the finalcopolymer prepared in these Examples (at a maximum of 22.7 wt-%) whichare each also prepared with significant amounts of another hydrophobicmonomer butyl acrylate (BA). A styrene chaser monomer is always presentin the final product (at least 1.5 wt-%). These examples teach away fromusing DBI or other higher itaconate esters to replace common hydrophobicmonomers such as BA, EHA and/or styrene. No significant improvement isseen in film properties such as hardness and water sensitivity of thecopolymers prepared in this document.

GB1009486 (Borden) describes a latex of composite polymeric particleswhere the core and shell may comprise a copolymer of a vinylidenechloride and an ester of an alpha unsaturated aliphatic acid (the amountof ester in the shell being greater than the core). One example (Example3) describes use of dibutyl itaconate (DBI) as the ester in an totalamount of 17% by weight of total monomers (5% in the outer shell and 12%in an inner non-core layer). These composite multi-layer polymerparticles address a problem of providing a water vapour barrier coatingfor paper and the like and they use much lower amounts of DBI than thepresent invention.

U.S. Pat. No. 3,766,112 describes a high gloss latex for floor polishcomprising a chlorinated paraffin wax with a polyvinyl pyrolidoneprotective colloid. Four monomer components used to prepare the colloid:styrene (70 to 85%), 2-ethylhexyl acrylate (EHA) (5 to 15%)(meth)acrylic acid (3 to 10%) and a fourth monomer (1 to 5%) allpercentages by weight of total monomers of the polyvinyl pyrolidone. Oneof the seven monomers suggested as the fourth monomer is DBI. Thesepolymers address the problem of providing high gloss floor coatings andDBI is used in much lower amounts than in the present invention.

Therefore broadly in accordance with the present invention there isprovided a copolymer having a low molecular weight (Low MW) and highglass transition temperature (High TG) the copolymer comprising(preferably consisting essentially of) moieties obtained and/orobtainable from the following components:

-   -   (a) at least 20 wt-% of one or more itaconate functional        monomer(s) not containing acidic groups or precursor acid groups        (also referred to herein as ‘Itaconate Monomer’),    -   (b) not more than 40 wt-% of an acid functional monomer(s) in an        amount sufficient to achieve an acid value from 65 to 325 mg KOH        per g of solid polymer (also referred to herein as ‘Acidic        Monomer’)    -   (c) optionally not more than 72 wt-% of other monomers not being        either (a) or (b) (also referred to herein as ‘Other Monomer’);    -   where the weight percentages of monomers (a), (b) and (c) total        100% and are calculated as a proportion of the total amount of        monomers in the copolymer being 100%; and with the provisos:    -   (I) the copolymer has a number average molecular weight (M_(a))        of no more than 15 kilograms/mole (also referred to herein as        ‘Low MW’); and    -   (II) the copolymer has a glass transition temperature of at        least 75° C. (also referred to herein as ‘High TG’),    -   and where optionally either or both of provisos (III)        and/or (IV) apply:    -   (III) the copolymer contains less than 40 wt-% vinyl aromatic        monomer(s) (also referred to herein as ‘Low Vinyl Aromatic’ or        Low-Styrene’); and/or    -   (IV) the copolymer contains less than 40 wt-% methacrylate        monomer(s) (also referred to herein as low-MA').

Optionally the copolymers of the invention are solid grade oligomers(SGO).

It is preferred that polymers of the invention, and/or the itaconatemonomers are obtained from bio-renewable sources.

A further aspect of the present invention comprises a coatingcomposition comprising from 5 to 80 wt-% of the total composition of aLow MW and High TG copolymer of the invention as described herein.

Copolymers of the invention may also be independently limited by one ormore of the following optional provisos:

-   -   (V) when component (a) consists of DBI in an amount of less than        30% by weight of the total monomers then the copolymer is        substantially free of any chloro groups; and    -   (VI) when component (a) consists of DBI in an amount of less        than 23% by weight of the total monomers then the copolymer is        prepared by other than an emulsion polymerisation method in        which a chaser monomer is used; and    -   (VII) when component (a) consists of DBI in an amount of less        than 23% by weight of the total monomers then if component (d)        is present, component (d) is other than styrene or a mixture        consisting of butyl acrylate (60 wt-% of mixture) and styrene        (40 wt-% of mixture)    -   (VIII) the copolymer is substantially free of styrene        (preferably styrene free), more preferably component (d) if        present is other than styrene or a mixture consisting of butyl        acrylate (60 wt-% of mixture) and styrene (40 wt-% of mixture),        more preferably component (d) if present is other than styrene        (S), butyl acrylate (BA), 2-ethyl hexyl; acrylate (EHA) or        mixtures thereof.    -   (IX) is prepared by other than an emulsion polymerisation method        in which a chaser monomer is used; and    -   (X) the copolymer is prepared by other than an emulsion        polymerisation method in which a chaser monomer is used        optionally this proviso applying only when component (a)        consists of DBI preferably in an amount of from 8.5 to 15% by        weight of the total monomers (a)+(b)+(c)+(d).    -   (XI) when component (a) consists of DBI then component (a) is        present in an amount other than 8.5 wt-%, 21.8 wt-%, 22.5 wt-%        or 22.7 wt % of the total monomer composition, preferably other        than from 8 wt-% to 23 wt %,    -   (XII) when component (a) consists of DBI then component (a) is        present in an amount other than 4.7 wt-%, 5.0 wt-%, 8.5 wt-%,        21.8 wt-%, 22.5 wt-%, 22.7 wt %, 25.0 wt-%, 28.7 wt-%, 30.0 wt-%        or 41.2 wt-% of the total monomer composition, preferably other        than from 4 wt-% to 42 wt %,    -   (XIII) the copolymer is obtained other than from a        polymerisation of a dimethyl itaconate (DMI) and dibutyl        itaconate (DBI) in the respective weight ratio of 15 to 85 in        the presence of poly diethyl itaconate seed polymer; more        preferably the copolymer is obtained other than from        polymerisation of dialkyl itaconate(s) in the presence of a poly        diethyl itaconate seed polymer; most preferably the copolymer is        obtained other than from polymerisation in the presence of a        poly dialkyl itaconate seed polymer; and/or    -   (XIV) if polymerisation of the copolymer occurs in the presence        of an initator system comprising organoborane amine complex and        an activator then component (a) is present in an amount greater        than 20 wt-%, preferably at least 24 wt-% of total monomers        (a)+(b)+(c)+(d).        As used herein the term seed polymer is as defined in        US2011-144265 (e.g. see paragraph [007]) i.e. a polymer seed        particle is dispersed in an aqueous medium such that the seed        particle absorbs further added (co)monomer and the seed particle        is present at a concentration to allow for control of particle        size of that (co)monomer.

Provisos (I) Low MW

Copolymers of the invention preferably have a number average molecularweight (M_(n)) of no more than 15 kilograms/mole (defined herein as LowMW), conveniently less than 10 kilograms/mole. Preferred copolymers ofthe invention have a number average molecular weight from 500 to 10000g/mole, more preferably from 500 to 7000 g/mole, most preferably from500 to 5000 g/mole, for example from 700 to 3000 g/mole.

(II) High TG

Copolymers of the invention have a high glass transition temperature ofat least 75° C. (defined herein as High TG) as calculated using the Foxequation. Preferred High TG copolymers of the invention have a glasstransition temperature of at least 80° C., more preferably at least 85°C., most preferably at least 90° C. for example at least 100° C.

(III) Low Vinyl Aromatic

The copolymer according to the invention may contain less than 40 wt-%of vinyl aromatic monomer(s), more preferably less than 20 wt-%, mostpreferably less than 10 wt-%, and even most preferably less than 5 wt-%,for example is substantially free of, (such as 0 wt-%) of vinyl aromaticmonomer(s) by weight of the total monomers being 100%. The limits towhat is meant herein by ‘substantially free’ are also as defined laterIt is optionally desired to limit the amount of vinyl aromatic monomerin the compositions and copolymers of the invention as their presencemay result in yellowing, reduced outdoor durability, and may havepotential adverse environmental and/or health impacts.

It is preferably desirable that copolymers and compositions of theinvention comprise low amounts of vinyl aromatic monomer(s) such asstyrene and/or other arylalkylene monomer(s). As used herein the termvinyl aromatic monomer(s) denotes monomers such as styrene, alpha-methylstyrene, vinyl toluene, vinyl anthracene, p-methyl styrene, andchloromethyl styrene. The term arylalkylene is also defined below. It ismore preferred that monomers such as styrene and α-methyl styrene arepresent in low amounts (or absent) from compositions of the invention.Most preferred compositions of the invention are those that aresubstantially free of vinyl aromatics. If a vinyl aromatic monomer isused in the invention, is conventionally styrene.

However as described in the section on acidic monomers by using lowmolecular weight polymers of high AV it can be possible to use higheramounts of vinyl aromatic monomers (up to 40% by weight of monomers).Nevertheless in a convenient embodiment of the invention the copolymerscomprise only a small amount of vinyl aromatic monomers (<20% by weightof monomers) and conveniently copolymers of the invention aresubstantially free of any vinyl aromatic monomers.

Surprisingly the applicant has discovered that embodiments of theinvention in which the copolymer contains none or low amounts of vinylaromatic monomers, the copolymer may be also be prepared by an improvedpolymerisation process that exhibits preferably at least one, morepreferably two, most preferably three of the following features (I) to(III):

-   -   (I) uses no more than 1 weight parts, preferably no more than        0.5, more preferably no more than 0.2, even more preferably no        more than 0.1 parts by weight, most preferably no chain transfer        agent; relative to the total monomer composition (i.e.        (a)+(b)+(c)) being 100 parts by weight (also denoted herein as        wt parts per 100 monomer)    -   (II) uses no more than 1 mole parts of initiator, preferably no        more than 0.5, more preferably no more than 0.2, even more        preferably no more than 0.1 parts by mole relative to the total        monomer composition (i.e. (a)+(b)+(c)) being 100 mole parts;        (also denoted herein as mole parts per 100 monomer) and/or    -   (III) has a maximum polymerisation temperature of no more than        275° C., preferably no more than 225° C., more preferably no        more than 200° C.

(IV) Low Methacrylate (Low-MA)

The copolymer according to the invention may contain less than 40 wt-%of methacrylate monomer(s), more preferably less than 20 wt-%, mostpreferably less than 10 wt-%, and even most preferably less than 5 wt-%,for example is substantially free of, such as 0 wt-% of MA monomer(s) byweight of the total monomers being 100%. The limits to what is meantherein by ‘substantially free’ are also as defined later. It is desiredto limit the amount of MA monomer in the compositions and copolymers ofthe invention for the reasons already given.

(III) and (IV) Low-Styrene and Low-MA

The copolymers and compositions of the invention may also comprise lowamounts of both vinyl aromatic monomer(s) and MA, usefully the totalamount of vinyl aromatic monomer(s) and MA monomer(s) is less than 40wt-%, more usefully less than 20 wt-%, most usefully less than 10 wt-%,and even most usefully less than 5 wt-%, for example is substantiallyfree of (such as 0 wt-%) of such monomer(s) by weight of the totalmonomers being 100%. The limits to what is meant herein by‘substantially free’ are also as defined later.

Component Monomers

Components (a), (b) and (c) are mutually exclusive. Thus it will beappreciated that acid functional monomers that may also be derived fromitaconates, such as itaconic acid, itaconic anhydride, half itaconateesters, acid derivatives thereof, combinations and/or mixtures thereofare considered part of the acid component (b) and are not part of theitaconate functional component (a)

In one preferred embodiment of the invention components (a) and (b) areeach derived from itaconates and/or derivatives thereof, more preferablyfrom a biorenewable source. Thus for example component (a) may be adi(C₁₋₆dialkyl)itaconate, (e.g. DBI and/or DMI) and component (b) may beitaconic anhydride and/or C₁₋₄alkyl monoester thereof (e.g. itaconicacid). In such an embodiment optionally there is no component (c) so thecopolymer may advantageously be obtained from monomers from the sameitaconate source.

Component (a) ITACONATE MONOMER

Itaconate functional monomers that are suitable for use as component (a)in the present invention may be represented generally by Formula 1:

where Ra and Rb independently represent any optionally substitutedhydrocarbon moiety (such as any aliphatic, cycloaliphatic or aromaticmoieties); andX and Y independently represent —O— and/or —NRc-, where Rc independentlyin each case represents H and/or any optionally substituted hydrocarbomoiety (such as any aliphatic, cycloaliphatic or aromatic moieties);with the proviso that Formula 1 does not contain:any acidic groups (such as carboxylic, phosphoric and/or sulphonic acidgroups) or any precursor acid groups, that is a group which readilygenerates an acid group under the conditions of polymerisation herein(such as an anhydride group).

When X and Y are both 0, Formula 1 represents 2-methylidenebutanedioatediesters (also referred to herein as itaconate diesters).

X and Y are both NRc, Formula 1 represents itaconate diamides.

When one or X or Y is O and the other is NRc Formula 1 represents acompound having one ester and one amide group.

It will be appreciated that the term itaconate functional monomer(s) asused herein denotes any itaconate diester and/or diamide monomers ofFormula 1 (as defined herein), other itaconate esters, itaconate amides,

Preferred itaconate functional monomers are those of Formula 1 where Raand Rb independently represent:

optionally substituted C₁₋₃₀hydrocarbyl,more preferably C₁₋₂₀alkylene (which may comprise linear, branchedand/or cyclic moieties) and/or C₃₋₂₀arylene;most preferably C₁₋₁₀alkylene.

Whilst Ra and Rb may be different, more conveniently they representidentical moieties.

Conveniently Formula 1 may represent dialkyl or aryl esters of itaconicacid, dialkyl or aryl amides of itaconic acid. More conveniently Ra andRb may be independently selected from the group consisting of: methyl,ethyl, n-propyl, i-propyl, n-butyl, i-butyl, t-butyl, hexyl, cyclohexyl,2-ethylhexyl, decyl, dodecyl, phenyl, 2-phenylethyl, 2-hydroxyethyl,2-hydroxypropyl, 3-hydroxypropyl, and 4-hydroxybutyl. More convenientlyRa and Rd are selected from: methyl, ethyl, n-butyl and 2-ethylhexyl.Most conveniently Ra and Rb are selected from methyl and ethyl forexample methyl.

The itaconate functional component (a) is present in the compositionsand/or copolymers of the invention in an amount of at least 20 wt-%,usefully at least 25 wt-%, more usefully at least 30 wt-%, even moreusefully at least 35 wt-% and most usefully at least 40 wt-%, based onthe total weight of monomers (a), (b) and (c) used to prepare thecopolymer being 100%.

Conveniently the itaconate functional component (a) may be present inthe compositions and/or copolymers of the invention in an amount of lessthan 80 wt-%, more conveniently less than 75 wt-%, even moreconveniently less than 70 wt-%, most conveniently less than 65 wt-%, andfor example less than 60 wt-%; based on the total weight of monomers(a), (b) and (c) used to prepare the copolymer being 100%.

Preferably the itaconate functional component (a) may be present in thecompositions and/or copolymers of the invention in an amount of from 20to 80 wt-%, more preferably from 25 to 75 wt-%, even more preferablyfrom 30 to 70 wt-%, most preferably from 35 to 65 wt-%, for example from40 to 60 wt-% based on the total weight of monomers (a), (b) and (c)used to prepare the copolymer being 100%.

Itaconate functional monomers such as those represented by Formula 1 mayalso be broadly divided into two types higher itaconate esters which aregenerally hydrophobic and lower itaconate esters which are generallyhydrophilic

In one embodiment of the invention the itaconate functional monomer maybe an itaconate diester of Formula 1 where Ra and Rb are independentlyoptionally substituted C₁₋₃hydrocarbo groups, such as C₁₋₃alkyl, anexample of which is dimethyl itaconate (DMI).

In another embodiment of the invention the itaconate functional monomermay be an itaconate diester of Formula 1 where Ra and Rb areindependently optionally substituted C₁₋₃hydrocarbo groups, such asC₁₋₃alkyl, an example of which is dibutyl itaconate (DBI).

The itaconate functional monomers (a) may be selected from thoseitaconate monomers that form homopolymers having a Tg of preferably morethan 40° C., more preferred more than 60° C., and most preferred morethan 80° C.

Component (b) ACIDIC MONOMER (Also Referred to as ‘Acidic Component’)

It will be understood that when referring to acid functional and/oracidic components herein refers to both acidic moieties (such ascarboxylic, phosphoric and/or sulphonic acid groups) and/or precursoracidic moieties which under the conditions of use may form acidic groups(e.g. anhydrides). An acid bearing monomer could be polymerised as thefree acid or as a salt, e.g. the ammonium and/or alkali metal saltthereof. References herein to acids should therefore also be understoodto include suitable salts and/or derivatives thereof (such as anhydridesand/or acid chlorides thereof).

Thus copolymers of the invention comprise acidic functional monomers(component (b)) that comprise an acid group and/or a precursor acidgroup. Suitable acid monomers can be monofunctional or difunctional inpotential acid functionality. Preferred monomers are acrylic acid,methacrylic acid, β-carboxyethyl acrylate, itaconic acid, itaconicanhydride, maleic acid, and maleic anhydride.

Other preferred acids have one ethylenic group and one or two carboxygroups. Such acid monomers are selected from the group consisting of:acrylic acid (and copolymerisable oligomers thereof), citraconic acid,mesaconic acid, crotonic acid, fumaric acid, itaconic acid, maleic acid,methacrylic acid, methylene malonic acid, anhydrides thereof, saltsthereof, acid chlorides thereof, phosphated hydroxylethyl methacrylate(phosphated HEMA), phosphated hydroxylethyl acrylate (phosphated HEA),phosphated hydroxylpropyl methacrylate (phosphated HPMA), phosphatedhydroxylpropyl acrylate (phosphated HPA), sulphonated styrene (and itschloride), 2-acrylamido-2-methylpropane sulfonic acid (AMPS) andethylmethacrylate-2-sulphonic acid, partial acids of multivalent esters,more preferably. half esters of diesters, most preferably mono acid halfitaconate esters (i.e. those esters of Formula A where either R_(a) orR_(b) is H). combinations thereof in the same species and/or mixturesthereof.

More preferred monomers are acrylic acid, methacrylic acid,β-carboxyethyl acrylate, and itaconic anhydride. The most preferred acidfunctional monomer is itaconic anhydride.

Suitable acid functional monomers of Component (b) are those that areco-polymerisable with the itaconate functional monomer(s) of component(a). Conveniently at least one monomer of component (b) may comprise atleast one activated unsaturated moiety as defined herein.

Usefully the monomer of component (b) is an acid functionalethylenically unsaturated monomer for example an acid functional(meth)acrylic monomer.

Preferred acidic monomers comprise, advantageously consist essentiallyof, at least one ethylenically unsaturated carboxylic acid althoughother acid groups such as optionally substituted organo phosphoricand/or sulphonic acids may also be used.

Examples include phosphated alkyl (meth)acrylates, sulphonic acids (andderivatives thereof) of arylalkylenes, sulphonic acids (and derivativesthereof) of alkyl (meth)acrylates and/or other organo substitutedsulphonic acids (such as acrylamidoalkyl sulfonic acids).

Useful arylalkylene sulphonic acids are those where the arylalkylenemoiety comprises optionally hydrocarbo substituted styrene, convenientlyoptionally C₁₋₁₀hydrocarbyl substituted styrene more convenientlyoptionally C₁₋₄alkyl substituted styrene. Useful acids are sulphonicacid substituted derivatives of styrenic compounds selected from thegroup consisting of styrene, α-methyl styrene, vinyl toluene, t-butylstyrene, di-methyl styrene and/or mixtures thereof. Especially preferredis styrene p-sulphonic acid and its corresponding acid chloride styrenep-sulphonyl chloride. However it is a preferred object of the inventionto reduce (in one embodiment preferably eliminate) the amount of vinylaromatic moieties (such as styrene and the like) in the copolymers ofthe invention. Therefore arylalkylene sulphonic acids are not preferredfor use as the acidic monomer (b) or if present are in such amounts tosatisfy proviso (III) that the copolymer of the invention comprises lessthan 40% of vinyl aromatic monomer.

Preferred phosphated organo acids comprise phosphated (meth)acrylatesoptionally substituted for example with one or more hydroxyl groups, forexample phosphated hydroxy(meth)acrylates and C₁₋₄alkyl esters thereof.

Particularly preferred acid monomers are acrylic acid, methacrylic acid,beta carboxy ethyl acrylate, itaconic acid, and/or itaconic anhydride.

It is known that certain acidic components which may or may notthemselves polymerise directly to form copolymers of the invention mayalso act as precursors for other monomers that undergo polymerisation toform a copolymer of the invention. For example at sufficiently hightemperatures in one embodiment of the invention itaconic acid willdehydrate to form itaconic anhydride in situ which may be then react asa monomer in a copolymerisation to form a copolymer of the invention.

For emulsion polymerization acidic monomers such as acrylic acid,methacrylic acid, beta carboxy ethyl acrylate, and/or itaconic acid maybe convenient. For a Solvent Assisted Dispersion (SAD) copolymerizationacidic monomers such as acrylic acid, methacrylic acid, and/or itaconicanhydride are preferred.

Usefully the acidic component (b) may be present in the compositionsand/or copolymers of the invention in an amount of at least 10 wt-%,more usefully at least 15 wt-%, even more usefully at least 20 wt-%,most usefully at least 25 wt-%, based on the total weight of monomers(a), (b) and (c) used to prepare the copolymer being 100%.

The Acidic Monomer (b) is present in the compositions and/or copolymersof the invention in an amount not more than 40 wt-%, conveniently lessthan 35 wt-%, more conveniently less than 30 wt-%; based on the totalweight of monomers (a), (b) and (c) used to prepare the copolymer being100%.

Preferably (and subject to the caveats relating to AV values below) theacidic component (b) may be present in the compositions and/orcopolymers of the invention in an amount of from 10 to 40 wt-%, morepreferably from 15 to 40 wt-%, even more preferably from 20 to 40 wt-%,most preferably from 25 to 40 wt-%, for example from 25 to 35 wt-% basedon the total weight of monomers (a), (b) and (c) used to prepare thecopolymer being 100%.

Usefully the acid monomer (b) may be present in the compositions and/orcopolymers of the invention in an amount sufficient amount to achieve anacid value (AV) of at least 80 mg KOH/g, more usefully at least 120 mgKOH/g, most usefully at least 160 mg KOH/g, for example at least 195 mgKOH/g of solid polymer

Conveniently the acid monomer (b) may be present in the compositionsand/or copolymers of the invention in an amount sufficient amount toachieve AV of no more than 325 mg KOH/g, more conveniently no more than290 mg KOH/g, most conveniently no more than 260 mg KOH/g, for exampleno more than 200 mg KOH/g of solid polymer.

Preferably the acid monomer (b) may be present in the compositionsand/or copolymers of the invention in an amount sufficient amount toachieve AV from 65 to 325 mg KOH/g. of solid polymer.

It is an optional object of the invention to limit the amount of vinylaromatic monomer as far as possible for the various reasons describedherein. However the applicant has surprisingly discovered that theprocessing difficulties with use of higher amounts (up to 40% by weight)of vinyl aromatic monomer can be compensated to some extent byincreasing AV number. Therefore in various alternative embodiments ofthe present invention the acid monomer may be present in thecompositions and/or copolymers of the invention in various amountssufficient to achieve certain acid values (in KOH/g per g of solidpolymer) when the copolymer contains certain corresponding total amountsof vinyl aromatic monomer (in % by weight of total monomers of thecopolymer):

Acid Value (AV) Vinyl Aromatic Monomer from 200 to 325 mg KOH/g withfrom 30 up to 40 weight %; or from 160 to 290 mg KOH/g with, from 20 upto 30 weight %; or from 120 to 260 mg KOH/g with from 10 up to 20 weight%; or from 80 to 195 mg KOH/g with from 0 up to 10 weight %.

Usefully component (b) satisfies both the acid value (AV) and weightlimits herein, but it will be appreciated that depending on the monomerused the AV specified herein may be achieved using weight percentagesoutside those preferred wt-% values given herein. Where there is anapparent inconsistency herein between any weight % of monomer or othercomponent and the acid values specified it will be appreciated thatsatisfying the AV is generally the more desirable objective. Ifnecessary the values for weight % of the relevant ingredients can bemodified appropriately in a manner well known to a skilled person.

The acidic functional monomers (b) may be selected from those acidicmonomers (or precursors therefore) that form homopolymers having a Tg ofpreferably more than 40° C., more preferred more than 60° C., and mostpreferred more than 80° C.

Component (c)—OTHER MONOMERS

The copolymers of the invention comprise no more than 72 wt-%,preferably no more than 70 wt-%, preferably no more than 60 wt-%, morepreferably no more than 40 wt-% of other monomers (component (c)) thatare neither itaconate functional monomers (a) nor acid functionalmonomers (b). Component (c) may also satisfy proviso (III) and/or (IV)that the copolymer of the invention comprises less than 40% of vinylaromatic monomer and/or less than 40% of methacrylate monomers.Therefore monomers such as arylalkylene and/or methacrylate monomersdescribed herein are preferred as component (c) only to the limitedextent described herein and optionally are substantially absent from thecompositions of the invention.

Conveniently the other monomers of component (c) may be present in thecompositions and/or copolymers of the invention in an amount of lessthan 30 wt-%, more conveniently less than 20 wt-%, even moreconveniently less than 10 wt-% and most conveniently less than 5 wt-%,based on the total weight of monomers (a), (b) and (c) used to preparethe copolymer being 100%.

Usefully where present the other monomers of component (c) are presentin the compositions and/or copolymers of the invention in an amount ofat least 0.1 wt-%, more usefully at least 0.5 wt-%, even more usefullyat least 5 wt-%, based on the total weight of monomers (a), (b) and (c)used to prepare the copolymer being 100%.

Preferably the other monomers of component (c) may be present in thecompositions and/or copolymers of the invention in an amount of from 0.1to 40 wt-%, more preferably from 0.5 to 40 wt-%, even more preferablyfrom 5 to 40 wt-%, most preferably from 5 to 30 wt-%, for example from 5to 20 wt-% based on the total weight of monomers (a), (b) and (c) usedto prepare the copolymer being 100%.

Suitable non-itaconate functional non acid functional monomers are givenbelow. Preferably component (c) comprises low amounts of (morepreferably is other than) vinyl aromatic monomers and/or arylalkylenemonomers.

The non-itaconate functional monomers can comprise any acrylic ormethacrylic acid ester or amide having a homopolymer Tg of preferablymore than 40° C., more preferred more than 60° C., and most preferredmore than 80° C.

Preferred examples of such monomers are methyl methacrylate, ethylmethacrylate, diacetone acrylamide, acrylonitrile, hydroxyethylmethacrylate, cyclohexyl methacrylate, isobornyl (meth)acrylate,polyethylene (meth)acrylate, polypropylene (meth)acrylate, acryl amideand methacryl amide. Specifically preferred crosslinking monomers thatcan be used to prepare the low molecular weight copolymer of theinvention are described in WO2005/097854 (DSM).

Component (c) comprises monomers not part of components (a), or (b))that are copolymerisable with them in any suitable technique such as anyof those described herein (for example in a SAD, solution, bulk, and/oran emulsion polymerisation).

Component (c) may comprise a suitable activated unsaturated moiety (suchas ethylenic unsaturation) where the structure(s) of component (c) donot overlap with any of components (a) or (b)).

Preferably component (c) is used in an amount of less than 50% and morepreferably less than 40% by weight.

Component (c) may comprise monomers that can undergo crosslinking, thatcan improve adhesion of the coating to various substrates, that canenhance the colloidal stability of the polymer emulsion, or that can beused to affect Tg, or polymer polarity.

Component (c) may also comprise crosslinking monomers that can inducecrosslinking of the copolymer composition. Crosslinking can occur atambient temperatures (using for instance diacetone acryl amide combinedwith adipic dihydrazide), at elevated temperatures (stoving conditionsin which for instance copolymerized hydroxyethyl (meth)acrylate reactswith hexamethoxy methyl melamines), or as 2C composition (copolymerizedhydroxyethyl (meth)acrylate reacting with polyisocyanates, such asBayhydur 3100). Other examples of crosslinking monomers includehydroxypropyl (meth)acrylate, silane functional monomers, such as3-methacryloxypropyl trimethoxysilane (Geniosil GF31, ex Wacker). Whenthe intention is to use the coating composition as a UV coating theaqueous composition comprising the low molecular weight polymeraccording to the invention, may be admixed with polymers or oligomershaving multiple unsaturated groups are admixed. Typical examples includedi- or tri-functional multifunctional acrylates such as trimethylolpropane triacrylate or ethoxylated or propoxylated versions thereof).

Preferably, the crosslinking monomer(s) is used in concentrations ofless than 15 wt-%, more preferably less than 10 wt-%, and mostpreferably between 0 and 10 wt-%.

Component (c) may also comprise monomers that improve (wet) adhesionproperties. Typical monomers include ureido functional monomers, such asPlex 6852-0 (ex. Evonik), i-bornyl (meth)acrylate, polyethylene(meth)acrylate, polypropylene (meth)acrylate.

Preferably, the adhesion promoting monomer(s) is used in concentrationsof less than 15 wt-%, more preferably less than 10 wt-%, and mostpreferably between 0 and 10 wt-%.

Optionally component (c) may also comprise least one polymerprecursor(s) of Formula 3

where Y denotes an electronegative group,R₆ is H, OH or an optionally hydroxy substituted C₁₋₁₀hydrocarbonR₇ is H or a C₁₋₁₀hydrocarbon;R₈ is a C₁₋₁₀hydrocarbo group substituted by at least one activatedunsaturated moiety; and; either:A represents a divalent organo moiety attached to both the —HN— and —Y—moieties so the -A-, —NH—, —C(═O)— and —Y— moieties together represent aring of 4 to 8 ring atoms, and R₇ and R₈ are attached to any suitablepoint on the ring; orA is not present (and Formula 3 represents a linear and/or branchedmoiety that does not comprise a heterocyclic ring) in which case R₇ andR₈ are attached to R₆; andm is an integer from 1 to 4.

The ring moiet(ies) of Formula 3 are each attached to R₈ and in Formula3 when m is 2, 3 or 4 then R₈ is multi-valent (depending on the value ofm). If m is not 1 R₇ and —Y— may respectively denote the same ordifferent moieties in each ring, preferably the same respective moietiesin each ring. R₇ and R₈ may be attached at any suitable position on thering.

Preferred monomers of Formula 3 comprise, conveniently consistessentially of, those where: A represents an optional substituteddivalent C₁₋₅hydrocarbylene; and

—Y— is divalent —NR₉— (where R₉ is H, OH, optionally hydroxy substitutedC₁₋₁₀hydrocarbo or R₈) or divalent O,

More preferred monomers of Formula 3 comprise those where: m is 1 or 2

—Y— is —NR₈— (i.e. where Formula 2 is attached to R₈ via a ringnitrogen), A represents a divalent C₁₋₃hydrocarbylene; R₆ is H, R₇ is aC₁₋₁₀hydrocarbo; andR₈ comprises a (meth)acryloxyhydrocarbon group or derivative thereof(e.g. maleic anhydride).

Monomers represented by Formula 3 include some monomers informallyreferred to as ureido monomers. Further suitable ureido monomers ofFormula 3 are described in “Novel wet adhesion monomers for use in latexpaints” Singh et al, Progress in Organic Coatings, 34 (1998), 214-219,(see especially sections 2.2 & 2.3) and EP 0629672 (National Starch)both of which are hereby incorporated by reference. Conveniently themonomers of Formula 3 may be used as a substantially pure compound (ormixture of compounds) or may be dissolved in a suitable solvent such asa suitable (meth)acrylate or acrylic derivative for example methylmethacrylate.

Another suitable adhesion promoting monomer ishydroxypropylcarbamatacrylate (HPCA) which for example is availablecommercially from BASF as a 70% solution in ethanol (HPCA 70% EtOH)

HPCA has the structure

and is useful as a (wet) adhesion promoter and/or crosslinker. It may bebiobased and/or produced by enzymes.

Other and/or additional component (d) may be used in those cases wherehigher molecular weights are desired, such as suitable multi functional(meth)acrylates or divinyl aromatics. Typical examples include di-,tri-, or tetra-functional (meth)acrylates, especially difunctional(meth)acrylates and divinyl benzene. Typical concentrations are lessthan 10%, more preferred less than 5%, even more preferred between 0.05and 4%, most preferred between 0.1 and 2.5%, and even most preferredbetween 0.15 and 1.5% by weight based on total monomers.

Other Aspects of the Invention Processes

The present invention relates to the selection of the monomers andproperties of the resultant copolymer. The polymerisation process bywhich copolymers of the invention may be prepared is not especiallyimportant as any suitable conventional polymerisation process may beused.

In one preferred embodiment of the invention the copolymer is preparedby a bulk polymerisation process. In another preferred embodiment of theinvention the copolymer is prepared by a solution polymerisationprocess. In still other preferred embodiment of the invention thecopolymer is prepared by a suspension polymerisation process. In a yetother preferred embodiment of the invention the copolymer is prepared byan emulsion polymerisation process. Details of these techniques aredescribed later.

Chain Transfer Agent (CTA)

In one preference in any embodiment of the invention which uses apolymerisation process where a chain transfer agent may usually havebeen required (such as but not limited to a radical polymerisation, suchas an emulsion polymerisation for example using the low styreneembodiment described herein) the process of the invention uses chaintransfer agent in the following total amounts relative to the totalmonomer composition (i.e. (a)+(b)+(c)) being 100%:

No more than 1 wt-%, preferably no more than 0.5%, more preferably nomore than 0.2%, even more preferably no more than 0.1%, most preferablyless than 50 ppm, for example no chain transfer agent.

Typical chain transfer agents that have been used in the prior artinclude mercapto-acids and alkyl esters thereof, carbon tetrabromide,mixtures thereof and cobalt chelate, dodecylmercaptane (DDM) being oneof the most commonly used. Mercapto chain transfer agent have beengenerally used in amounts of less than 1 wt-% based on the total monomercontent. Typically cobalt chelate CTAs are used in amounts of less than50 ppm of Co on total weight of copolymer.

Initator

In one preference in any embodiment of the invention which uses apolymerisation process where an initiator may usually have been requiredthe process of the invention uses initiator in the following totalamounts relative to the total monomer composition (i.e. (a)+(b)+(c))being 100%:

For a bulk or solution polymerisation process, no more than 1 mole-%,preferably no more than 0.5 mole-%, more preferably no more than 0.2mole-%, even more preferably no more than 0.1 mole-%.

For an emulsion polymerisation process, no more than 1.5 mole-%,preferably no more than 1 mole-%, more preferably no more than 0.75mole-%, even more preferably no more than 0.5 mole-%.

Initiators for radical polymerization of monomers to make vinyl polymersare well known and are any which are normally suitable for free-radicalpolymerisation of acrylate monomers. They may be oil-soluble and havelow solubility in water such as organic peroxides, organic peroxyestersand organic azo initiators and are generally used in an amount of about0.1 to 2 wt-% based on the total monomer content.

The applicant has found that in general especially for the embodiment ofthe invention that has lower amounts of vinyl aromatic monomer thenlower amounts of initiator can be used to prepare the itaconatefunctional polymers of the invention than would be used to preparepolymers where a methacrylate monomer is used (in whole or in part)rather the itaconate functional monomer (component (a)).

Subject to the optional limitations on initiator described herein,initiators that can be used to produce the low molecular weight polymervia solution or bulk polymerization can be any organic peroxide,including hydroperoxides, dialkyl peroxides, and/or alkylperoxyalkanoates.

Examples of suitable initiators may also comprise any of the followingand/or suitable mixtures thereof (as well as chemically similar and/oranalogous initiators—for example of the same structural type—as any ofthose listed below):

All those available commercially from Akzo-Nobel under the Laurox®,Perkadox® and/or Trigonox® trademarks and/or trade designations such asgiven in parentheses below:

diisobutyryl peroxide (Trigonox® 187-C30 and/or 187-W40);cumyl peroxyneodecanoate (Trigonox® 99-C75 and/or 99-W50);di(3-methoxybutyl) peroxydicarbonate (Trigonox® 181);1,1,3,3-tetramethylbutyl peroxyneodecanoate (Trigonox® 423-C70 and/or423-W50);cumyl peroxyneoheptanoate (Trigonox® 197-C75);tert-amyl peroxyneodecanoate (Trigonox® 123-C75);the mixtures of peroxydicarbonates available under the trademarksTrigonox® ADC and/or Trigonox® ADC-NS60;di-sec-butyl peroxydicarbonate (Trigonox® SBP, SBP-C60, SBPS and/orSBPS-C60);diisopropyl peroxydicarbonate (Perkadox® IPP-NA30 and/or IPP-NA27);di(4-tert-butylcyclohexyl) peroxydicarbonate (Perkadox® 16S, 16, 16-W75and/or 16-W40);di(2-ethylhexyl) peroxydicarbonate (Trigonox® EHP-C75, EHP-W60, EHP—W50,EHP-W40S, EHPS and/or EHPS-C75);tert-butyl peroxyneodecanoate (Trigonox® 23, 23-C75, 23-C30 and/or23-W50);dibutyl peroxydicarbonate (Trigonox® NBP-050);dicetyl peroxydicarbonate (Perkadox® 24-FL, 24L and/or 24-W35);dimyristyl peroxydicarbonate (Perkadox® 26);1,1,3-tetramethylbutyl peroxypivalate (Trigonox® 425-C75);tert-butyl peroxyneoheptanoate (Trigonox® 257-C75);tert-amyl peroxypivalate (Trigonox® 125-C75);tert-butyl peroxypivalate (Trigonox® 25-C75, 25-C40 and/or 25-C25);di(3,3,5-trimethylhexanoyl) peroxide (Trigonox® 36-C75, 36-C40, 36-C37.5and/or 36-W50);dilauroyl peroxide (Laurox®, Laurox® S and/or Laurox® W-40);didecanoyl peroxide (Perkadox® SE-10);2,2-azodi(isobutyronitrile) (Perkadox® AIBN);2,2-azodi(2-methylbutyronitrile) (Perkadox® AMBN and/or AMBN-GR);2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane (Trigonox® 141);1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate (Trigonox® 421);tert-amyl peroxy-2-ethylhexanoate (Trigonox® 121 and/or 121-C75);dibenzoyl peroxide (Perkadox® L-W75, L-W75 SF, L-W40, CH-50, API and/orL-DFG) tert-butyl peroxy-2-ethylhexanoate (Trigonox® 21S, 21-C70, 21-050and/or 21-C30);tert-butyl peroxydiethylacetate (Trigonox® 27);tert-butyl peroxyisobutyrate (Trigonox® 41-050);1,1′-azodi(hexahydrobenzonitrile) (Perkadox® ACCN);1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane (Trigonox® 29,29-B90 and/or 29-C75);1,1-di(tert-amylperoxy)cyclohexane (Trigonox® 122-C80);1,1-di(tert-butylperoxy)cyclohexane (Trigonox® 22-B50, 22-E50 and/or22-C80);tert-amylperoxy 2-ethylhexyl carbonate (Trigonox® 131);tert-amylperoxy acetate (Trigonox® 133-CK60);tert-butyl peroxy-3,3,5-trimethylhexanoate (Trigonox® 42S, 42-C60 and/or42-C30);2,2-di(tert-butylperoxy)butane (Trigonox® D-050 and/or D-E50);tert-butylperoxy isopropyl carbonate (Trigonox® BPIC-C75);tert-butylperoxy 2-ethylhexyl carbonate (Trigonox® 117);tert-amyl peroxybenzoate (Trigonox® 127);tert-butyl peroxyacetate (Trigonox® F-050);butyl 4,4-di(tert-butylperoxy)valerate (Trigonox® 17);tert-butyl peroxybenzoate (Trigonox® C and/or C-C75);dicumyl peroxide (Perkadox® BC-FF);di(tert-butylperoxyisopropyl)benzene(s) (Perkadox® 14S and/or 14S-FL);2,5-dimethyl-2,5-di(tert-butylperoxy)hexane (Trigonox® 101, 101-50D-PD,101-20PP, 101-7.5PP-PD and/or 101-E50);tert-butyl cumyl peroxide (Trigonox® T);2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3 (Trigonox® 145-E85);di-tert-butyl peroxide (Trigonox® B, B-C75, B-C50 and/or B-C30);3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxonane (Trigonox® 301 and/or301-20PP);isopropylcumyl peroxide (Trigonox® M-55);1,1,3,3-tetramethylbutyl hydroperoxide (Trigonox® TMBH-L);3,3,5,7,7-pentamethyl-1,2,4-trioxepane (Trigonox® 311);cumyl hydroperoxide (Trigonox® K-90);tert-butyl hydroperoxide (Trigonox® A-80 and/or A-W70);tert-amyl hydroperoxide (Trigonox® TAHP-W85); and/or2,3-dimethyl-2,3-diphenylbutane (Perkadox® 30).

Temperature.

In one preference in any embodiment of the process of the invention (forexample low styrene embodiment of the process of the invention) themaximum polymerisation temperature exhibited is as follows:

For a bulk polymerisation process, no more than 275° C., preferably nomore than 225° C., more preferably no more than 200° C.

For a solution polymerisation process, no more than 180° C., morepreferably no more than 160° C., and most preferably no more than 150°C.

For an emulsion or dispersion polymerisation process, no more than 130°C., more preferably no more than 120° C., and typically no more than100° C.

It is appreciated that in those cases where the polymerisationtemperature is higher than the boiling point of the solvent (or water inthe case of emulsion or dispersion polymerisation), this implicates thatthe polymerisation is performed at a pressure of higher than 1 bar.

Optionally certain copolymers of the invention may also be limited bythe following optional provisos:

-   -   (I) when component (a) consists of DBI in an amount of less than        30% by weight of the total monomers then the copolymer is        substantially free of any chloro group; and    -   (II) when component (a) consists of DBI in an amount of from 8.5        to 15% by weight of the total monomers the copolymer is prepared        by other than an emulsion polymerisation method in which a        chaser monomer is used.

Conveniently the composition is substantially free of polyvinyl chloridepolymer and/or chlorinated paraffin wax, more preferably issubstantially free of any monomer comprising chloro groups, mostpreferably is substantially free of any species comprising Cl whether asa substituent, atom, di-molecule, ion or otherwise

A further aspect of the invention provides a coating compositioncomprising between 5 and 80 wt-% of a low molecular weight polymer(s)characterized by that the low molecular weight (Low MW) polymercomprises at least 20 wt-% of itaconate functional monomer(s), and has anumber average molecular weight of from 500 to 10000 g/mole.

The polymer of the invention has a low number average molecular weight(Low MW polymer) and can be made via emulsion polymerization, dispersionpolymerization, (continuous) bulk polymerization or via solutionpolymerization. The preferred polymerization processes are bulkpolymerization and solution polymerization. Where Low MW polymers of theinvention are prepared via emulsion, dispersion and/or solutionpolymerization, the monomer composition can be added in differentsequential phases.

The Low MW polymer of the invention is preferably used as colloidalstabilizer in a second stage emulsion polymerization. For this purpose,the acid groups of the low molecular weight polymer are (partially)neutralized and the low molecular weight polymer is (partially)dissolved prior to starting the emulsion polymerization stage. The lowMW polymer can, however, also be advantageously used as additive to asecond polymer emulsion. In these cases an alkaline solution of the lowMW polymer is admixed after the polymerisation process of the secondpolymer emulsion is completed.

Preferred copolymers of the invention have a polydispersity of from 2 to2.5, more preferably about 2.5. Therefore suitable desired correspondingvalues for weight average molecular weight of the copolymers of theinvention can be calculated by multiplying each of the values given fornumber average molecular weight herein by 2.5. Such calculated weightaverage molecular weight values and ranges are disclosed herein withoutbeing recited explicitly.

Broadly there is provided in a yet further aspect of the presentinvention a process for preparing a copolymer comprising the step ofpolymerising polymer precursors in a polymerisation method the polymerprecursors comprising component (a), component (b) and optionallycomponent (c) as described above to obtain a copolymer.

Preferably the polymerisation method is selected from bulk, solution,suspension and/or emulsion polymerisation, more preferably bulkpolymerisation.

Another aspect of the invention broadly provides for a copolymerobtained and/or obtainable by a process of the present invention.

In a yet another embodiment of the invention the copolymer may beprepared by a continuous bulk polymerization for example using a methodanalogous to that described in WO82/02387 or EP554783. Thus for examplethe Low MW polymer may be prepared using (continuous) bulkpolymerization, preferably using a solvent concentration of less than 40wt-% (based on solid polymer being 100%), more preferably using lessthan 20 wt-% of solvent. Examples of suitable solvents and suitableinitiators (subject to the optional limitations described herein) canalso be found in WO82/02387 or EP554783 the contents of both of whichare hereby incorporated by reference.

In the case that the low molecular weight polymer is prepared usingsolution polymerization, the preferred solvents are those having aboiling point of not more than 130° C., more preferred not more than100° C., and most preferred not more than 90° C.

Preferred solvents are acetone, methylethyl ketone, methanol, ethanol,i-propanol, ethyl acetate, butyl acetate and/or toluene. Other suitablesolvents will be well known to those skilled in the art. In those caseswhere the polymerization temperature exceeds that of the boiling pointsof solvent and/or monomer, the polymerization will be performed underincreased pressure.

Preferably, the solids content of the solution polymer is at least 40wt-%, more preferred between 50 and 90 wt-%, most preferred between 60and 85 wt-%. Usefully the solid polymer of the invention is obtained byremoval of substantially all of the solvent used during the solutionpolymerisation step and the solid polymer so isolated has a solidcontent of at least 95%, more preferably at least 98%, most preferablyat least 99%. Conveniently the solid polymer of the invention obtainedby solution polymerisation is isolated in amorphous form (e.g. as flakesor pellets) or in crystalline form (e.g. as needle like crystals).

The low molecular weight polymer prepared via solution polymerizationcan be dissolved by increasing pH and next be used as is. It is,however, preferred when the solvent used in the polymerization step isremoved after the low molecular weight polymer is dissolved is waterusing a base. Removal of the solvent can be done by increasingtemperature or reducing pressure. It is preferred to combine these.Solvent can be removed after dissolving the low molecular weight polymerprior to further use. It can, however, be envisaged that solvent canalso be removed after the low molecular weight polymer is used in thesubsequent steps that are elaborated below.

Although less preferred the low molecular weight polymer can also beprepared via emulsion polymerization or dispersion polymerization bytechniques well known to those skilled in the art.

In a special embodiment where itaconic anhydride or maleic anhydride areused as acid functional monomers, they may be modified after completionof the polymerization. Modification of the anhydride groups can occurwith any nucleophilic functionality. Preferred functionalities includehydroxyl groups, hydrazide groups, hydrazine groups, semi-carbazidegroups and amine groups. In all cases, modification will result in theintroduction of the moiety attached to the hydroxyl, hydrazide,hydrazine, semi-carbazide or amine group and, simultaneously, of an acidgroup. The remaining acid group can subsequently be used for dissolvingthe low molecular weight polymer.

The modification can be done with monofunctional hydroxyl groups,hydrazide, or hydrazine, or primary, or secondary amines, but also withdi-functional or higher functional hydroxyl, hydrazine, hydrazide,semi-carbazide, or primary or secondary amines. Potential hydroxylfunctionalities can include C1-C20 aliphatic, aromatic, orcycloaliphatic mono-, di-, or high functional alcohols. The aliphatic,aromatic, or cycloaliphatic groups can include other functionalitiesthat can, for instance, be used for improved adhesion, crosslinking orother purposes. Typical examples of such functionalities can includephosphate, phosphonate, sulphate, sulphonate, ketone, silane, (cyclic)ureido, (cyclic) carbonate, hydrazide, hydrazine, semi-carbazide,urethane, urea, carbamate, and melamine.

The preferred (poly)amines, (poly)hydrazines, or (poly)hydrazides arewell known to those skilled in the art and include those describedherein.

When the low molecular weight polymer comprises itaconic anhydride ormaleic anhydride that is to be used in a modification step, it isstrongly preferred that the anhydride is not hydrolysed prior to thereaction with hydroxyl or amine functional moieties. Hence, in thosecases the preferred polymerization methods are bulk polymerizationand/or solution polymerization, where the solvent is non-protic.

The low molecular weight polymer of the invention can be dissolved inwater according to various procedures especially where it comprises acidfunctional groups (e.g. introduced by an acid monomer). For example thelow molecular weight polymer can be added to water, followed byneutralizing the acid groups to a sufficiently high level, the acidgroups of the low molecular weight polymer can be neutralized prior toaddition to water, or the water used to dissolve the low MW polymer isneutralised prior to addition of the low MW polymer. Each of these stepscan be performed at ambient or at elevated temperatures (i.e. higherthan ambient).

A further aspect of the invention provides for a coating compositioncomprising a low molecular weight polymer as described herein. The lowmolecular weight polymer can be introduced to the coating composition indifferent ways, non-limiting examples of which are described below:

The low molecular weight polymer can be blended or admixed for examplewith a preformed latex. This can be done by dissolving the low molecularweight polymer first and next admixing it with a second emulsion(s) orthe low molecular weight polymer can be dissolved in second emulsion(s).The second emulsion(s) can be any type of polymer emulsion, includingpolyvinyl compositions, comprising sequential, oligomer supported,gradient morphology emulsions, polyurethane emulsions, urethane-acrylateemulsions, alkyd emulsions, and/or polyester emulsions.

The low molecular weight polymer, which is dissolved in water, can beused as a surfactant and/or stabilizer for the emulsion polymerizationstep. An example of such a process can be found in Comparative example 1in WO2005/097854.

The low molecular weight polymer can be used as a pigment dispersant forexample by added to a coating composition by first mixing it in apigment dispersion. In this case the low molecular weight polymer isadded to a pigment dispersion comprising inorganic pigment particles andthe mixture grinded until a stable pigment dispersion is obtained. Next,the pigment dispersion is added to a polymer emulsion(s) to form apigmented coating.

Preferred application areas for compositions and/or coatings or theinvention include wood coatings, such as joinery, industrial wood,parquet, and decorative applications, adhesive and graphic artsapplications, such as inks, adhesives, overprint varnishes, filmcoatings, coatings for application on various plastics, such aspolystyrene, polyester, PVC, polypropylene, polyethylene, or applicationto glass or metal.

Copolymers of the invention may be formed using a number of processes.These include emulsion polymerisation, suspension polymerisation, bulkpolymerisation and solution polymerisation. Such processes are extremelywell known and need not be described in great detail.

In one embodiment the copolymers of the invention may be made using abulk polymerisation process. Bulk polymerisation of olefinicallyunsaturated monomers is described in detail in EP 0156170, WO82/02387,and U.S. Pat. No. 4,414,370 the contents of which are herebyincorporated by reference. In general in a bulk polymerisation process amixture of two or more monomers are charged preferably continuously intoa reactor zone containing molten vinyl polymer having the same ratio ofvinyl monomers as the monomer mixture. The molten mixture is maintainedat a preset temperature to provide a vinyl polymer of the desiredmolecular weight. The product is pumped out of the reaction zone at thesame rates as the monomers are charged to the reaction zone to provide afixed level of vinyl monomer and vinyl polymer in the system. Theparticular flow rate selected will depend upon the reaction temperature,vinyl monomers, desired molecular weight and desired polydispersity.

In another embodiment emulsion polymerisation may be used to formcopolymers of the invention. A conventional emulsion process involvesdispersing the monomers in an aqueous medium and conductingpolymerisation using a free-radical initiator (normally water soluble)and appropriate heating (e.g. 30 to 120 C°) and agitation.

The aqueous emulsion polymerisation can be effected with conventionalemulsifying agents (surfactants) being used such as anionic and/ornon-ionic emulsifiers. The amount used is preferably low, preferably 0.3to 2% by weight, more usually 0.3 to 1% by weight based on the weight oftotal monomers charged.

The aqueous emulsion polymerisation can employ conventional free radicalinitiators such as peroxides, persulphates and redox systems as are wellknown in the art. The amount of initiator used is generally 0.05 to 3%based on the weight of total monomers charged.

The aqueous emulsion polymerisation process may be carried out using an“all-in-one” batch process (i.e. a process in which all the componentsto be employed are present in the polymerisation medium at the start ofpolymerisation) or a semi-batch process in which one or more of thecomponents employed (usually at least one of the monomers), is wholly orpartially fed to the polymerisation medium during the polymerisation.Although not preferred, fully continuous processes could also be used inprinciple. Preferably a semi-batch process is employed.

The polymerisation technique employed may be such that a low molecularweight polymer is formed, e.g. by employing a chain transfer agent suchas one selected from mercaptans (thiols), certain halohydrocarbons andalpha-methyl styrene; or catalytic chain transfer polymerisation usingfor example cobalt chelate complexes as is quite conventional.Alternatively a controlled radical polymerisation process can be used,for instance by making use of an appropriate nitroxide or athiocarbonylthio compounds such as dithioesters, dithiocarbamates,trithiocarbonates, and xanthates in order to mediate the polymerizationvia for example a nitrox mediated polymerisation (NMP), a reversibleaddition fragmentation chain-transfer process (RAFT) or atom transferradical polymerization (ATRP).

When the copolymer of the invention is an emulsion polymer it may bemixed with a variety of other polymer emulsions such as those that donot comprise DBI (or higher itaconate esters). Examples of such secondpolymer emulsions can be polyurethane emulsions,polyurethane-poly(meth)acrylate emulsions, alkyd emulsions, polyesteremulsions and/or polyvinyl emulsions. This latter group of copolymeremulsions may comprise oligomer-polymer emulsions, gradient morphologyemulsions, sequentially polymerized emulsions, or single phase copolymeremulsions.

The emulsions according to the description above can be produced viaemulsion polymerization or via a process called solvent assisteddispersion (SAD) polymerization.

When the copolymer emulsion is produced via emulsion polymerization thiscan be according to a single feed process, a sequentially fedmulti-phase copolymerization process, or a power feed process, resultingin a gradient particle morphology.

In the case of a solution polymerization process, the polymerization isperformed in organic solvents. Next, base and/or surfactant are addedand the polymer solution is emulsified. Preferably, the solvent isremoved via evaporation at the end of the complete process.

Solution polymers can be produced via as single feed solutionpolymerization or by a sequentially fed multi-phase polymerization. Itis also envisaged that a solution polymer, prior or after the optionalremoval of the solvent, is used as a seed for an emulsion polymerizationstage. In this case, the polymer emulsion prepared according to thesolution polymerisation process is used as seed in a batch or semi-batchpolymerization process.

The preferred polymerization process is a bulk of solutionpolymerisation.

Surfactants are used in emulsion polymerization as known to thoseskilled in the art. Typical surfactants have been extensively describedin all kinds of patent applications. The choice and concentration ofsurfactants are not deemed to be critical for this invention. Theaqueous emulsion polymerisation can be effected with conventionalemulsifying agents (surfactants) being used such as anionic and/ornon-ionic emulsifiers. The amount used is preferably low, preferably 0.3to 2% by weight, more usually 0.3 to 1% by weight based on the weight oftotal monomers charged to make the polymer.

Preferably (and subject to the provisos herein) in one embodiment of theinvention the process of making a copolymer emulsion of the inventioncomprises using a chaser monomer composition as described inWO2011073417. In another embodiment a chaser monomer may optionally notbe used.

In a preferred case the residual monomer content of the low MW copolymeremulsion is below 2000 mg/L, more preferred below 1500 mg/L, mostpreferred below 1000 mg/L, and especially preferred below 550 mg/L.

If it is desired to crosslink polymers (for example in a polymerdispersion), the relevant low MW copolymers can carry functional groupssuch as hydroxyl groups and the dispersion subsequently formulated witha crosslinking agent such as a polyisocyanate, melamine, or glycoluril;or the functional groups on one or both polymers could include keto oraldehyde carbonyl groups and the subsequently formulated crosslinker instep c) could be a polyamine or polyhydrazide such as adipic aciddihydrazide, oxalic acid dihydrazide, phthalic acid dihydrazide,terephthalic acid dihydrazide, isophorone diamine and4,7-dioxadecane-1,10 diamine. It will be noted that such crosslinkingagents will effect crosslinking by virtue of forming covalent bonds.

Whilst the term vinyl polymer is commonly used to refer to thermoplasticpolymers derived by polymerization from compounds containing the vinylgroup (CH₂═CH—), the term “vinyl polymer” is used herein more broadly todenote any polymer (whether thermoplastic or not) that comprises (e.g.as repeat units therein) and/or is derived from monomers and/or polymerprecursors comprising one or more of the following moieties: activatedunsaturated moieties (such as acrylates and/or methacrylates); anyolefinically unsaturated moieties (such as vinyl moieties); mixturesthereof; and/or combinations thereof within the same moiety.

There is an increasing demand to use bio-renewable monomers in order toimprove the sustainability of the polymers used in for example coatingapplications. In view of concerns about depletion of fossil fuelresources or an increase in carbon dioxide in the air that poses aglobal-scale environmental problem in recent years, methods forproducing raw materials of these polymers from biomass resources haveattracted a lot of attention. Since these resources are renewable andtherefore have a carbon-neutral biomass, such methods are expected togain in particular importance in future. It is therefore a preferredfeature of the present invention and the aspects described herein thatwhere possible the monomers (especially the higher itaconate diesterssuch as DBI) as far as possible are biorenewable.

Preferably at least 20 wt-%, more preferably at least 30 wt-%, andespecially 40 wt-% of the olefinically unsaturated monomers used to formthe polymers of the invention are derived from at least onebio-renewable olefinically unsaturated monomer. Bio-renewable monomersmay be obtained fully or in part from bio-renewable sources. In apreferred embodiment methacrylate monomers are used as monomer (c) wherethe alcohol is made from biorenewable sources. In yet another preferredembodiment both the (meth)acrylate unit and the possible alcohol aremade from biorenewable sources. Thus it is preferred to also measure thecarbon-14 content to determine the biorenewability.

The content of carbon-14 (C-14) is indicative of the age of a bio-basedmaterial. It is known in the art that C-14, which has a half life ofabout 5,700 years, is found in bio-renewable materials but not in fossilfuels. Thus, “bio-renewable materials” refer to organic materials inwhich the carbon comes from non-fossil biological sources. Examples ofbio-renewable materials include, but are not limited to, sugars,starches, corns, natural fibres, sugarcanes, beets, citrus fruits, woodyplants, cellulosics, lignocelluosics, hemicelluloses, potatoes, plantoils, other polysaccharides such as pectin, chitin, levan, and pullulan,and a combination thereof.

C-14 levels can be determined by measuring its decay process(disintegrations per minute per gram carbon or dpm/gC) through liquidscintillation counting. In one embodiment of the present invention,polymer A and or polymer B comprise at least about 1.5 dpm/gC(disintegrations per minute per gram carbon) of carbon-14, morepreferably at least 2 dpm/gC, most preferably at least 2.5 dpm/gC, andespecially at least 4 dpm/gC.

Acrylic acid can be made from glycerol, as is disclosed by Arkema, orfrom lactic acid as described by U.S. Pat. No. 7,687,661. Methacrylicacid can be prepared from ethene, methanol and carbon monoxide (allbio-renewable), as disclosed by Lucite International Ltd.

Olefinically unsaturated bio-renewable monomers which may additionallyprovide a contribution to improved coating properties includeα-methylene butyrolactone, α-methylene valerolactone, α-methylene γ-R³butyrolactone (R³ can be an optionally substituted alkyl or optionallysubstituted aryl); itaconates such as dialkyl itaconates (including DBI)and monoalkyl itaconates, itaconic acid, itaconic anhydride, crotonicacid and alkyl esters thereof, citraconic acid and alkyl esters thereof,methylene malonic acid and its mono and dialkyl esters, citraconicanhydride, mesaconic acid and alkyl esters thereof.

Another useful set of useful bio-renewable monomers include N—R²,α-methylene butyrolactam (R² can be an optionally substituted alkyl oroptionally substituted aryl); N—R², α-methylene γ-R¹ butyrolactam;N-alkyl itaconimids; furfuryl (meth)acrylate; fatty acid functional(meth)acrylates such as DAPRO FX-522 from Elementis and Visiomer® MUMAfrom Evonik.

It is appreciated that certain features of the invention, which are forclarity described in the context of separate embodiments may also beprovided in combination in a single embodiment. Conversely variousfeatures of the invention, which are for brevity, described in thecontext of a single embodiment, may also be provided separately or inany suitable sub-combination.

The object of the present invention is to solve some or all of theproblems or disadvantages (such as identified throughout the applicationherein) with the prior art.

Unless the context clearly indicates otherwise, as used herein pluralforms of the terms herein are to be construed as including the singularform and vice versa.

The term “comprising” as used herein will be understood to mean that thelist following is non-exhaustive and may or may not include any otheradditional suitable items, for example one or more further feature(s),component(s), ingredient(s) and/or substituent(s) as appropriate.

The terms ‘effective’, ‘acceptable’ ‘active’ and/or ‘suitable’ (forexample with reference to any process, use, method, application,preparation, product, material, formulation, compound, monomer,oligomer, polymer precursor, and/or polymers described herein asappropriate) will be understood to refer to those features of theinvention which if used in the correct manner provide the requiredproperties to that which they are added and/or incorporated to be ofutility as described herein. Such utility may be direct for examplewhere a material has the required properties for the aforementioned usesand/or indirect for example where a material has use as a syntheticintermediate and/or diagnostic tool in preparing other materials ofdirect utility. As used herein these terms also denote that a functionalgroup is compatible with producing effective, acceptable, active and/orsuitable end products.

Preferred utility of the present invention comprises as component of acoating composition.

In the discussion of the invention herein, unless stated to thecontrary, the disclosure of alternative values for the upper and lowerlimit of the permitted range of a parameter coupled with an indicatedthat one of said values is more preferred than the other, is to beconstrued as an implied statement that each intermediate value of saidparameter, lying between the more preferred and less preferred of saidalternatives is itself preferred to said less preferred value and alsoto each less preferred value and said intermediate value.

For all upper and/or lower boundaries of any parameters given herein,the boundary value is included in the value for each parameter. It willalso be understood that all combinations of preferred and/orintermediate minimum and maximum boundary values of the parametersdescribed herein in various embodiments of the invention may also beused to define alternative ranges for each parameter for various otherembodiments and/or preferences of the invention whether or not thecombination of such values has been specifically disclosed herein.

Thus for example a substance stated as present herein in an amount from0 to “x” (e.g. in units of mass and/or weight %) is meant (unless thecontext clearly indicates otherwise) to encompass both of twoalternatives, firstly a broader alternative that the substance mayoptionally not be present (when the amount is zero) or present only inan de-minimus amount below that can be detected. A second preferredalternative (denoted by a lower amount of zero in a range for amount ofsubstance) indicates that the substance is present, and zero indicatesthat the lower amount is a very small trace amount for example anyamount sufficient to be detected by suitable conventional analyticaltechniques and more preferably zero denotes that the lower limit ofamount of substance is greater than or equal to 0.001 by weight %(calculated as described herein).

It will be understood that the total sum of any quantities expressedherein as percentages cannot (allowing for rounding errors) exceed 100%.For example the sum of all components of which the composition of theinvention (or part(s) thereof) comprises may, when expressed as a weight(or other) percentage of the composition (or the same part(s) thereof),total 100% allowing for rounding errors. However where a list ofcomponents is non-exhaustive the sum of the percentage for each of suchcomponents may be less than 100% to allow a certain percentage foradditional amount(s) of any additional component(s) that may not beexplicitly described herein.

In the present invention, unless the context clearly indicatesotherwise, an amount of an ingredient stated to be present in thecomposition of the invention when expressed as a weight percentage, iscalculated based on the total amount of monomers in the compositionbeing equivalent to 100% (thus for example components (a)+(b)+(c)+(d)total 100%). For convenience certain non-monomer ingredients (such asfor example chain transfer agents (CTA)) which fall outside thedefinitions of any of components (a) to (d) may also be calculated asweight percentages based on total monomer (i.e. where the weight oftotal monomers alone is set at 100%). As the weight % of monomers (forexample for components (a) to (d)) by definition total 100% it will beseen that using monomer based weight % values for the non-monomeringredients (i.e. those components outside (a) to (d)) will mean thetotal percentages will exceed 100%. Thus amounts of non-monomeringredients expressed as monomer based weight percentages can beconsidered as providing a ratio for the weight amounts for theseingredients with respect to the total weight of monomers which is usedonly as a reference for calculation rather than as a strict percentage.Further ingredients are not excluded from the composition when(a)+(b)+(c)+(d) total 100% and weight percentages based on totalmonomers should not be confused with weight percentages of the totalcomposition.

The term “substantially” and/or “substantially comprises” as used hereinmay refer to a quantity or entity to imply a large amount or proportionthereof. Where it is relevant in the context in which it is used“substantially” can be understood to mean quantitatively (in relation towhatever quantity or entity to which it refers in the context of thedescription) there comprises an proportion of at least 80%, preferablyat least 85%, more preferably at least 90%, most preferably at least95%, especially at least 98%, for example about 100% of the relevantwhole. By analogy the term “substantially-free” may similarly denotethat quantity or entity to which it refers comprises no more than 20%,preferably no more than 15%, more preferably no more than 10%, mostpreferably no more than 5%, especially no more than 2%, for exampleabout 0% of the relevant whole.

The terms ‘optional substituent’ and/or ‘optionally substituted’ as usedherein (unless followed by a list of other substituents) signifies theone or more of following groups (or substitution by these groups):carboxy, sulpho, formyl, hydroxy, amino, imino, nitrilo, mercapto,cyano, nitro, methyl, methoxy and/or combinations thereof. Theseoptional groups include all chemically possible combinations in the samemoiety of a plurality (preferably two) of the aforementioned groups(e.g. amino and sulphonyl if directly attached to each other represent asulphamoyl group). Preferred optional substituents comprise: carboxy,sulpho, hydroxy, amino, mercapto, cyano, methyl, halo, trihalomethyland/or methoxy.

The synonymous terms “organic substituent”, “moiety”, and “organicgroup” as used herein (also abbreviated herein to “organo”) denote anyunivalent or multivalent moiety (optionally attached to one or moreother moieties) which comprises one or more carbon atoms and optionallyone or more other heteroatoms. Organic groups may comprise organoheterylgroups (also known as organoelement groups) which comprise univalentgroups containing carbon, which are thus organic, but which have theirfree valence at an atom other than carbon (for example organothiogroups). Organic groups may alternatively or additionally compriseorganyl groups which comprise any organic substituent group, regardlessof functional type, having one free valence at a carbon atom. Organicgroups may also comprise heterocyclyl groups which comprise univalentgroups formed by removing a hydrogen atom from any ring atom of aheterocyclic compound: (a cyclic compound having as ring members atomsof at least two different elements, in this case one being carbon).Preferably the non carbon atoms in an organic group may be selectedfrom: hydrogen, halo, phosphorus, nitrogen, oxygen, silicon and/orsulphur, more preferably from hydrogen, nitrogen, oxygen, phosphorusand/or sulphur.

Most preferred organic groups comprise one or more of the followingcarbon containing moieties: alkyl, alkoxy, alkanoyl, carboxy, carbonyl,formyl and/or combinations thereof; optionally in combination with oneor more of the following heteroatom containing moieties: oxy, thio,sulphinyl, sulphonyl, amino, imino, nitrilo and/or combinations thereof.Organic groups include all chemically possible combinations in the samemoiety of a plurality (preferably two) of the aforementioned carboncontaining and/or heteroatom moieties (e.g. alkoxy and carbonyl ifdirectly attached to each other represent an alkoxycarbonyl group).

The term ‘hydrocarbo group’ as used herein is a sub-set of an organicgroup and denotes any univalent or multivalent moiety (optionallyattached to one or more other moieties) which consists of one or morehydrogen atoms and one or more carbon atoms and may comprise one or moresaturated, unsaturated and/or aromatic moieties. Hydrocarbo groups maycomprise one or more of the following groups. Hydrocarbyl groupscomprise univalent groups formed by removing a hydrogen atom from ahydrocarbon (for example alkyl). Hydrocarbylene groups comprise divalentgroups formed by removing two hydrogen atoms from a hydrocarbon, thefree valences of which are not engaged in a double bond (for examplealkylene). Hydrocarbylidene groups comprise divalent groups (which maybe represented by “R₂C═”) formed by removing two hydrogen atoms from thesame carbon atom of a hydrocarbon, the free valences of which areengaged in a double bond (for example alkylidene). Hydrocarbylidynegroups comprise trivalent groups (which may be represented by “RC≡”),formed by removing three hydrogen atoms from the same carbon atom of ahydrocarbon the free valences of which are engaged in a triple bond (forexample alkylidyne). Hydrocarbo groups may also comprise saturatedcarbon to carbon single bonds (e.g. in alkyl groups); unsaturated doubleand/or triple carbon to carbon bonds (e.g. in respectively alkenyl andalkynyl groups); aromatic groups (e.g. in aryl groups) and/orcombinations thereof within the same moiety and where indicated may besubstituted with other functional groups

The term ‘alkyl’ or its equivalent (e.g. ‘alk’) as used herein may bereadily replaced, where appropriate and unless the context clearlyindicates otherwise, by terms encompassing any other hydrocarbo groupsuch as those described herein (e.g. comprising double bonds, triplebonds, aromatic moieties (such as respectively alkenyl, alkynyl and/oraryl) and/or combinations thereof (e.g. aralkyl) as well as anymultivalent hydrocarbo species linking two or more moieties (such asbivalent hydrocarbylene radicals e.g. alkylene).

Any radical group or moiety mentioned herein (e.g. as a substituent) maybe a multivalent or a monovalent radical unless otherwise stated or thecontext clearly indicates otherwise (e.g. a bivalent hydrocarbylenemoiety linking two other moieties). However where indicated herein suchmonovalent or multivalent groups may still also comprise optionalsubstituents. A group which comprises a chain of three or more atomssignifies a group in which the chain wholly or in part may be linear,branched and/or form a ring (including spiro and/or fused rings). Thetotal number of certain atoms is specified for certain substituents forexample C_(1-N)organo, signifies a organo moiety comprising from 1 to Ncarbon atoms. In any of the formulae herein if one or more substituentsare not indicated as attached to any particular atom in a moiety (e.g.on a particular position along a chain and/or ring) the substituent mayreplace any H and/or may be located at any available position on themoiety which is chemically suitable and/or effective.

Preferably any of the organo groups listed herein comprise from 1 to 36carbon atoms, more preferably from 1 to 18. It is particularly preferredthat the number of carbon atoms in an organo group is from 1 to 12,especially from 1 to 10 inclusive, for example from 1 to 4 carbon atoms.

As used herein chemical terms (other than IUAPC names for specificallyidentified compounds) which comprise features which are given inparentheses—such as (alkyl)acrylate, (meth)acrylate and/or(co)polymer—denote that that part in parentheses is optional as thecontext dictates, so for example the term (meth)acrylate denotes bothmethacrylate and acrylate.

Certain moieties, species, groups, repeat units, compounds, oligomers,polymers, materials, mixtures, compositions and/or formulations whichcomprise and/or are used in some or all of the invention as describedherein may exist as one or more different forms such as any of those inthe following non exhaustive list: stereoisomers (such as enantiomers(e.g. E and/or Z forms), diastereoisomers and/or geometric isomers);tautomers (e.g. keto and/or enol forms), conformers, salts, zwitterions,complexes (such as chelates, clathrates, crown compounds,cyptands/cryptades, inclusion compounds, intercalation compounds,interstitial compounds, ligand complexes, organometallic complexes,non-stoichiometric complexes, π-adducts, solvates and/or hydrates);isotopically substituted forms, polymeric configurations [such as homoor copolymers, random, graft and/or block polymers, linear and/orbranched polymers (e.g. star and/or side branched), cross-linked and/ornetworked polymers, polymers obtainable from di and/or tri-valent repeatunits, dendrimers, polymers of different tacticity (e.g. isotactic,syndiotactic or atactic polymers)]; polymorphs (such as interstitialforms, crystalline forms and/or amorphous forms), different phases,solid solutions; and/or combinations thereof and/or mixtures thereofwhere possible. The present invention comprises and/or uses all suchforms which are effective as defined herein.

Polymers of the present invention may be prepared by one or moresuitable polymer precursor(s) which may be organic and/or inorganic andcomprise any suitable (co)monomer(s), (co)polymer(s) [includinghomopolymer(s)] and mixtures thereof which comprise moieties which arecapable of forming a bond with the or each polymer precursor(s) toprovide chain extension and/or cross-linking with another of the or eachpolymer precursor(s) via direct bond(s) as indicated herein.

Polymer precursors of the invention may comprise one or more monomer(s),oligomer(s), polymer(s); mixtures thereof and/or combinations thereofwhich have suitable polymerisable functionality. It will be understoodthat unless the context dictates otherwise term monomer as used hereinencompasses the term polymer precursor and does not necessarily excludemonomers that may themselves be polymeric and/or oligomeric incharacter.

A monomer is a substantially monodisperse compound of a low molecularweight (for example less than one thousand g/mole) which is capable ofbeing polymerised.

A polymer is a polydisperse mixture of macromolecules of large molecularweight (for example many thousands of g/mole) prepared by apolymerisation method, where the macromolecules comprises the multiplerepetition of smaller units (which may themselves be monomers, oligomersand/or polymers) and where (unless properties are critically dependenton fine details of the molecular structure) the addition or removal oneor a few of the units has a negligible effect on the properties of themacromolecule.

A oligomer is a polydisperse mixture of molecules having an intermediatemolecular weight between a monomer and polymer, the molecules comprisinga small plurality of monomer units the removal of one or a few of whichwould significantly vary the properties of the molecule.

Depending on the context the term polymer may or may not encompassoligomer.

The polymer precursor of and/or used in the invention may be prepared bydirect synthesis or (if the polymeric precursor is itself polymeric) bypolymerisation. If a polymerisable polymer is itself used as a polymerprecursor of and/or used in the invention it is preferred that such apolymer precursor has a low polydispersity, more preferably issubstantially monodisperse, to minimise the side reactions, number ofby-products and/or polydispersity in any polymeric material formed fromthis polymer precursor. The polymer precursor(s) may be substantiallyun-reactive at normal temperatures and pressures.

Except where indicated herein polymers and/or polymeric polymerprecursors of and/or used in the invention can be (co)polymerised by anysuitable means of polymerisation well known to those skilled in the art.Examples of suitable methods comprise: thermal initiation; chemicalinitiation by adding suitable agents; catalysis; and/or initiation usingan optional initiator followed by irradiation, for example withelectromagnetic radiation (photo-chemical initiation) at a suitablewavelength such as UV; and/or with other types of radiation such aselectron beams, alpha particles, neutrons and/or other particles.

The substituents on the repeating unit of a polymer and/or oligomer maybe selected to improve the compatibility of the materials with thepolymers and/or resins in which they may be formulated and/orincorporated for the uses described herein. Thus the size and length ofthe substituents may be selected to optimise the physical entanglementor interlocation with the resin or they may or may not comprise otherreactive entities capable of chemically reacting and/or cross linkingwith such other resins as appropriate.

Another aspect of the invention broadly provides a coating compositioncomprising the polymers and/or beads of the present invention and/or asdescribed herein.

A further aspect of the invention provides a coating obtained orobtainable from a coating composition of the present invention.

A yet other aspect of the invention broadly provides a substrate and/orarticle having coated thereon an (optionally cured) coating compositionof the present invention.

A yet further aspect of the invention broadly provides a method of usingpolymers of the present invention and/or as described herein to preparea coating composition.

A still further aspect of the invention broadly provides a method forpreparing a coated substrate and/or article comprising the steps ofapplying a coating composition of the present invention to the substrateand/or article and optionally curing said composition in situ to form acured coating thereon. The curing may be by any suitable means, such asthermally, by radiation and/or by use of a cross-linker.

Preferred coating compositions are solvent coating compositions oraqueous coating compositions, more preferably are aqueous coatingcompositions.

Optionally aqueous coating compositions may also comprise a co-solvent.A co-solvent, as is well known in the coating art, is an organic solventemployed in an aqueous composition to ameliorate the dryingcharacteristics thereof, and in particular to lower its minimum filmforming temperature. The co-solvent may be solvent incorporated or usedduring preparation of polymers of the invention or may have been addedduring formulation of the aqueous composition.

The compositions of the invention are particularly useful as or forproviding the principle component of coating formulations (i.e.composition intended for application to a substrate without furthertreatment or additions thereto) such as protective or decorative coatingcompositions (for example paint, lacquer or varnish) wherein aninitially prepared composition optionally may be further diluted withwater and/or organic solvents, and/or combined with further ingredientsor may be in more concentrated form by optional evaporation of waterand/or organic components of the liquid medium of an initially preparedcomposition.

The compositions of the invention may be used in various applicationsand for such purposes may be optionally further combined or formulatedwith other additives and/or components, such as defoamers, rheologycontrol agents, thickeners, dispersing and/or stabilizing agents(usually surfactants and/or emulsifiers), wetting agents, fillers,extenders, fungicides, bactericides, coalescing and wetting solvents orco-solvents (although solvents are not normally required), plasticisers,anti-freeze agents, waxes, colorants, pigments, dyes, heat stabilisers,levelling agents, anti-cratering agents, fillers, sedimentationinhibitors, UV absorbers, antioxidants, reactive diluents, neutralisingagents, adhesion promoters and/or any suitable mixtures thereof.

The aforementioned additives and/or components and the like may beintroduced at any stage of the production process or subsequently. It ispossible to include fire retardants (such as antimony oxide) to enhancefire retardant properties.

The compositions of the invention may also be blended with otherpolymers such as vinyl polymers, alkyds (saturated or unsaturated),polyesters and or polyurethanes.

The coating composition of the invention may be applied to a variety ofsubstrates including wood, board, metals, stone, concrete, glass, cloth,leather, paper, plastics, foam and the like, by any conventional methodincluding brushing, dipping, flow coating, spraying, and the like. Thecoating composition of the invention may also be used to coat theinterior and/or exterior surfaces of three-dimensional articles. Thecoating compositions of the invention may also be used, appropriatelyformulated if necessary, for the provision of films, polishes,varnishes, lacquers, paints, inks and adhesives. However, they areparticularly useful and suitable for providing the basis of protectivecoatings for substrates that comprise wood (e.g. wooden floors),plastics, polymeric materials, paper and/or metal.

The carrier medium may be removed from the compositions of the inventiononce they have been applied to a substrate by being allowed to drynaturally at ambient temperature, or the drying process may beaccelerated by heat. Crosslinking can be developed by allowing to standfor a prolonged period at ambient temperature (several days) or byheating at an elevated temperature (e.g. 50° C.) for a much shorterperiod of time.

A still further aspect of the present invention comprises paintsobtained, obtainable and/or comprising polymer compositions of theinvention, especially where polymers compositions of the invention areemulsion polymers. Thus for example paint made from the emulsion polymercompositions of this invention may contain pigment at pigment volumeconcentrations in the range of 0 to 85%, preferably in the range of 0 to55%. The pigment volume concentration of a species of pigment particlesis the percentage of the volume occupied by that species of pigmentparticles, based on the total volume of the dried coating prepared fromthe emulsion polymer compositions. Suitable pigments include inorganicpigments, such as titanium dioxide, iron oxide, zinc oxide, magnesiumsilicate, calcium carbonate, organic and inorganic coloured pigments,aluminosilicates, silica, and various clays. Titanium dioxide is apreferred for its ability to provide opacity. Suitable organic pigmentsalso include plastic pigments such as solid bead pigments andmicrosphere pigments containing voids or vesicles. Examples of solidbead pigments include polystyrene and polyvinyl chloride beads. Examplesof microsphere pigments, which include polymer particles containing oneor more voids and vesiculated polymer particles, are disclosed in U.S.Pat. No. 4,427,836, U.S. Pat. No. 4,920,160, U.S. Pat. No. 4,594,363,U.S. Pat. No. 4,469,825, U.S. Pat. No. 4,468,498, U.S. Pat. No.4,880,842, U.S. Pat. No. 4,985,064, U.S. Pat. No. 5,157,084, U.S. Pat.No. 5,041,464, U.S. Pat. No. 5,036,109, U.S. Pat. No. 5,409,776 and U.S.Pat. No. 5,510,422. Other suitable pigments include, for example,Expancel™ 551 DE20 acrylonitrile/vinyl chloride expanded particles(Expancel Inc. Duluth Ga.); Sil-Cell™ 35/34 sodium potassium aluminiumsilicate particles (Silbrico Corporation, Hodgkins Ill.); Dualite™ 27polyvinylidene chloride copolymer coated with CaCO₃ (Pierce and StevensCorporation, Buffalo N.Y.); Fillitte™ 150 ceramic spherical particles(Trelleborg Fillite Inc. Norcross Ga.); Microbeads™ 4A soda limeparticles (Cataphote Inc.); Sphericell™ hollow glass particles (PotterIndustries Inc. Valley Forge Pa.); Eccosphere™ hollow glass spheres (NewMetals & Chemicals Ltd.; Essex England); Z-light™ Zeeospheres W-410 andW-610 ceramic hollow spheres (3M St. Paul Minn.); Scotchlite™ K46 glassbubbles (3M St. Paul Minn.); Vistamer™ UH 1500 polyethylene particles;and Vistamer™ HD 1800 polyethylene particles (Fluoro-Seal Inc., HoustonTex.). Ropaque™ Polymer is a preferred component in the coatings.Z-light™ Zeeospheres W-410 and W-610 ceramic hollow spheres are alsopreferred components. Combinations of the above ingredients arefrequently preferred.

Paints prepared from emulsion polymer compositions comprising lowmolecular weight polymer of this invention may be thickened with variousaqueous thickening agents. These include but not are limited tohydrophobically modified alkali swellable emulsion such Acrysol™ TT-935,Acrysol™ TT-615, Acrysol™ RM-6, Polyphobe™ TR-116. Alkali swellableemulsions such as Acrysol™ ASE-60 may also be used. Hydrophobicallymodified water soluble polymers may also be used such as Acrysol™RM-2020, Acrysol™ RM-8, Aquaflow™ XLS-500, Aquaflow™ NHS-310, Rheolate™CVS-11, and hydrophobically modified HEC such as Natrosol™ Plus 330.Hydroxyethyl cellulose may also be used such as Natrosol™ HBR, orCellosize™ QP-3000. Clays such as Attagel™ 50 or Bentone™ DE may also beused for sagging and settling control.

Paints prepared from emulsion polymer compositions comprising lowmolecular weight polymer of this invention may utilize dispersants tohelp stabilize the pigments in the paint. Polyacid dispersants such asHydropalat™ 44, or hydrophobic copolymer dispersants such as Tamol™ 681,Tamol™ 165, and Tamol™ 731 may be used. Styrene Maleic anhydridecopolymers may also be used. Small molecule dispersants such aspolyphosphates and citric acid may also be used. Examples ofpolyphosphates include tetra-potassium pyrophosphate, potassiumtripolyphosphate, sodium hexameta phosphate, and higher phosphates soldunder the trade name Calgon™. The latter phosphates are used inconjunction with ZnO pigments to help provide stability.

Paints prepared from emulsion polymer compositions comprising lowmolecular weight polymer of this invention may utilize coalescing aidsto aid in the film formation of the latex emulsion polymers. Thesecoalescing aids can be volatile such as ethoxy and propoxy ethers ofcommon alcohols. Examples include ethylene glycol monobutyl ether,diethylene glycol monobutyl ether, propylene glycol monobutyl, anddipropylene glycol monobutyl ether. A common and preferred coalescingagent is Texanol™. Paints prepared from the emulsion polymercompositions of this invention may also utilize non volatile coalescingagents which do not contribute to VOC's. These coalescing agents wouldinclude materials like Optifilm™ 400, Dioctyl maleate, triethyl citrate,or tributyl phosphate. In some instances oxidatively curing reactiveplasticizers such as Oxi-Cure™ 100 may be used. In addition the paintmay also contain a humectant material such as ethylene glycol orpropylene glycol. Open time additives such as Rhodaline™ OTE, orOptifilm™ OT1200 may also be used. It is preferred that the paint madefrom the emulsion polymer compositions contain less than 5% VOC byweight based on total weight of the composition. More preferred arepaint compositions containing less than 2% VOC by weight, and mostpreferred are paint compositions containing less than 0.05% VOC byweight.

Paints prepared from emulsion polymer compositions comprising lowmolecular weight polymer of this invention will also contain addedsurfactants. These surfactants are used to improve substrate wetting,insure pigment and colorant compatibility, and improve stability.Nonionic surfactants such as ethoxylated alcohols are frequently addedto improve free/thaw stability and colorant compatibility. These wouldinclude low HLB nonionics such as Igepal™ CO-430, Igepal™ CO-630 andhigher HLB nonionics such as Triton X-405. For these surfactants it isalso desirable to use analogs based on alkyl alcohols such as tridecylalcohol, or branched secondary alcohols such as Tergitol™ TMN-10.Triton™ CF-10 is also quite commonly used to aid in pigment wetting.Dioctyl sulfosuccinates are frequently used to enhance substrate wettingsuch as Aerosol™ OT-100. Acetylenic diols such as Surfynol™ 104 can alsobe used and are sometimes desired due to their low dynamic surfacetension. Phosphate based surfactants can also be employed particularlyto improve TiO₂ compatibility and stability. These would includesurfactants from the Strodex™ line such as PK-90 or PK-0VOC.

Paints prepared from emulsion polymer compositions comprising lowmolecular weight polymer of this invention may also contain additiveswhich can alter the surface blocking characteristics. Such additiveswould include fluorocarbon surfactants such as Capstone™ FS-61.

Paints prepared from the emulsion polymer compositions of this inventionmay also contain multivalent metal ions to provide for post filmformation crosslinking. These multivalent metal ions will improve thehardness, and scratch resistance of the final paint as well as toimprove the chemical resistance. In particular it is seen that this willimprove resistance to organic solvents. Examples of multivalent metalions include Zn, Mg, Zr, and Ca. These are frequently added in the formof water soluble salts such as acetates or carbonates. Zinc AmmoniumCarbonate is frequently used to great advantage; however Mg(OH)₂ is alsoeffective and sometimes desired.

Paints prepared from emulsion polymer compositions comprising lowmolecular weight polymer of this invention may contain phosphate orborosilicate based corrosion inhibiting pigments such as Heucophos™ ZPO,Halox™ SPZ-391, Halox™ SZP-391 JM, Halox™ 430, or Halox™ CW-291. Thepaints prepared from the emulsion polymer compositions of this inventionmay contain organic corrosion inhibitors such as Halox™ 510, Halox™ 520or Halox™ 570. he paints prepared from the emulsion polymer compositionsof this invention may contain flash rust inhibitors such as nitritesalts, phosphate salts, benzoic acid salts, or Halox™ Flash-X 330. Theseingredients are typically added to a direct to metal coating to reduceflash rusting and long term corrosion.

Paints prepared from emulsion polymer compositions comprising lowmolecular weight polymer of this invention may contain tannin stainblocking additives to block the migration of tannins through thecoating. These additives are typically based on multivalent cations suchas Zr²⁺ and Zn²⁺ or solid inorganic materials capable of bindingnegatively charged tannins. The additives would include Stainban™ 185,Stainban™ 186, Stainban™ 187, Halox™ BW-100, Halox™ L-44, and Halox™1-66. In addition ZnO is frequently added to these paints to improvetannin stain blocking. In many instances it is particularly desired toprepare paints which contain inorganic pigments with high aspect ratios.An example would be a platy talc such as Vertal™ 7. This is known toimprove the tannin blocking character of the paint.

Paints prepared from emulsion polymer compositions comprising lowmolecular weight polymer of this invention may contain UV absorbers andfree radical scavengers. These are used to improve the long termexterior durability of a coating, or to protect the underlying substratefrom UV degradation. This is particularly useful when formulating clearto semi transparent wood stains. The UV blockers can be organicmaterials such as benzotriazoles, or can be inorganic UV blockers suchas sub 100 nm metal oxides. The free radical scavengers are based onhindered amine light stabilizers. Examples of UV blockers includeTinuvin 1130, trans iron oxides such as Tint-ayd CW5499 or Tint-aydCW5600, nano zinc oxide, and nano titanium oxide. Combinations ofTinuvin 1130 with Tint-ayd CW5499 are particularly useful for semitransparent wood stains.

Paints prepared from emulsion polymer compositions comprising lowmolecular weight polymer of this invention may contain waxes or surfacemodification additives such as silicone slip aids. Waxes may be used toreduce the gloss of the paint and maintain a high level of coffee, wine,or tea stain resistance. These waxes also can improve the burnishresistance of the coating. Examples of such waxes include Ceraflour™916, Ceraflour™ 920, and Ceraflour™ 962. Waxes may also be used toimprove the mar and scratch resistance of the paint. An example would beMichem Emulsion™ 39235. Slicone slip aids may also be used to improvemar and scratch. An example would be Tego Glide™ 410.

Paints prepared from emulsion polymer compositions comprising lowmolecular weight polymer of this invention may contain reactive silaneswhich contain an epoxy group or an amine group. The silane can be atrialkoxy, a dialkoxy, or a mono alkoxy. The alkoxy groups are typicallymethoxy, ethoxy, or propoxy. In the case of the dialkoxy, or a monoalkoxy materials the silicon atom is bonded to a methyl group. Forexample, monomethyldimethoxy silane would be common siloxane group.Trialkoxy, and dialkoxy silanes based on methoxy or ethoxy arepreferred. The emulsion polymer may also contain reactive groups such asepoxy or acetoacetoxy which can react with the amine functional portionof the amino silane. An example of a useful amino silane would beSilquest A-1100 which is □-amino propyl-triethoxysilane. □-aminopropylmethyldimethoxysilane is a useful coupling agent for adhesion tometal oxides such as aluminium oxide. An example of useful epoxy silanesare Silquest A-186 and Silquest A-187. The silanes are typically used ataround 1% and provide for adhesion to metals and metal oxide surfaces.They can also be used to crosslink the paint.

Many other variations embodiments of the invention will be apparent tothose skilled in the art and such variations are contemplated within thebroad scope of the present invention.

Further aspects of the invention and preferred features thereof aregiven in the claims herein.

Tests Minimum Film Forming Temperature

The minimum film forming temperature (MFFT) of a dispersion as usedherein is the temperature where the dispersion forms a smooth and crackfree coating or film using DIN 53787 and when applied using a Sheen MFFTbar SS3000.

Koenig Hardness

Koenig hardness as used herein is a standard measure of hardness, beinga determination of how the viscoelastic properties of a film formed fromthe dispersion slows down a swinging motion deforming the surface of thefilm, and is measured according to DIN 53157 NEN5319.

Glass Transition Temperature (Tg)

As is well known, the glass transition temperature of a polymer is thetemperature at which it changes from a glassy, brittle state to aplastic, rubbery state. The glass transition temperatures may bedetermined experimentally using Differential Scanning calorimetry (DSC),taking the peak of the derivative curve as Tg, or calculated from theFox equation. Thus the Tg, in degrees Kelvin, of a copolymer having “n”copolymerised comonomers is given by the weight fractions W of eachcomonomer type and the Tgs of the homopolymers (in degrees Kelvin)derived from each comonomer according to the equation:

$\frac{1}{Tg} = {\frac{W_{1}}{{Tg}_{1}} + \frac{W_{2}}{{Tg}_{2}} + {\ldots \mspace{14mu} \frac{W_{n}}{{Tg}_{n}}}}$

The calculated Tg in degrees Kelvin may be readily converted to ° C.

Solids Content

The solids content of an aqueous dispersion of the invention is usuallywithin the range of from about 20 to 65 wt-% on a total weight basis,more usually 30 to 55 wt-%. Solids content can, if desired, be adjustedby adding water or removing water (e.g. by distillation orultrafiltration).

pH Value

The pH value of the dispersion of the invention can be from 2 to 10 andmostly is from 6 to 9.5.

Blocking Block Resistance Measurement [Includes Blocking and EarlyBlocking]: Step 1: Blocking:

A 100 micron wet film of the aqueous emulsion of the invention to which10% butyldiglycol is added is cast on to a paper substrate and dried for16 hours at 52° C.

Step 1: Early Blocking:

A 250 micron wet film of the aqueous emulsion of the invention to which10% butyldiglycol was added, is cast on to a paper substrate and driedfor 24 hours at room temperature.

Step 2: Blocking and Early Blocking:

After cooling down to room temperature two pieces of coated film areplaced with the coated side against each other under a load of 1Kg/cm.sup.2 for 4 hours at 52° C. After this time interval the load onthe samples is removed and the samples are left to cool down to roomtemperature (22+−2° C.). When the two coatings can be removed from eachother without any damage to the film (do not stick) the block resistanceis very good and assessed as a 5. When they however completely sticktogether, block resistance is very bad and assessed as a 0.

Gas Chromatography Mass Spectrometry (GCMS)

to confirm polymerisation is substantially complete the content of freeitaconate ester monomers content can be determined by GCMS. The GCMSanalyses were performed on a Trace GC-DSQ MS (Interscience, Breda, theNetherlands) equipped with a CTC combi Pal robotic autosampler for headspace has been used. The carrier gas was Helium and a CP Sil 5 lowbleed/MS, 25 m×0.25 mm i.d., 1.0 μm (CP nr. 7862) column has been used.

The GC-oven was programmed from 50° C. (5 min) followed by differentsequential temperature ramps of 5° C./min to 70° C. (0 min), 15° C./minto 220° C. (0 min), and ending with 25° C./min to 280° C. (10 min). Acontinuous Helium flow of 1.2 ml/min was used. A hot split injection at300° C. was performed on a programmed temperature vaporizer (PTV). Theinjection volume was 1 μl. The MS transfer line and ion source were bothkept at 250° C. The samples were measured with single ion monitoring(SIM). For the specific case of dibutyl itaconate (DBI) the masses 127.0and 59.0 Da were used, for the internal standard (iso butyl acrylate)the masses 55.0 and 73.0 were applied. The sample solutions wereapproximately 500 mg in 3 ml of internal standard solution (iso butylacrylate in acetone). The calibration was performed with 5 differentconcentration levels from 0 to 500 ppm. The calculation was performedusing Microsoft Excel with a linear calibration curve.

Molecular Weight

Unless the context clearly dictates otherwise the term molecular weightof a polymer or oligomer as used herein denotes number average molecularweight (also denoted as M_(N)). M_(N) may be measured by any suitableconventional method for example by Gas Phase Chromatography(GPC—performed similarly to the GCMS method described above) and/or bythe SEC method described below. GPC method is preferred

Determination of Molecular Weight of a Polymer Using SEC

The molecular weight of a polymer may also be determined using

Size Exclusion Chromatography (SEC) with tetrahydrofuran as the eluentor with 1,1,1,3,3,3 hexafluoro isopropanol as the eluent.

1) Tetrahydrofuran

The SEC analyses were performed on an Alliance Separation Module (Waters2690), including a pump, auto injector, degasser, and column oven. Theeluent was tetrahydrofuran (THF) with the addition of 1.0 vol % aceticacid. The injection volume was 150 μl. The flow was established at 1.0ml/min. Three PL MixedB (Polymer Laboratories) with a guard column (3 μmPL) were applied at a temperature of 40° C. The detection was performedwith a differential refractive index detector (Waters 410). The samplesolutions were prepared with a concentration of 20 mg solids in 8 ml THF(+1 vol % acetic acid), and the samples were dissolved for a period of24 hours. Calibration is performed with eight polystyrene standards(polymer standard services), ranging from 500 to 4,000,000 g/mol. Thecalculation was performed with Millennium 32 software (Waters) with athird order calibration curve. The obtained molar masses are polystyreneequivalent molar masses (g/mol).

2) 1,1,1,3,3,3 Hexafluoro Isopropanol

The SEC analyses were performed on a Waters Alliance 2695 (pump,degasser and autosampler) with a Shodex RI-101 differential refractiveindex detector and Shimadzu CTO-20AC column oven. The eluent was1,1,1,3,3,3 hexafluoro isopropanol (HFIP) with the addition of 0.2Mpotassium trifluoro acetate (KTFA). The injection volume was 50 μl. Theflow was established at 0.8 ml/min. Two PSS PFG Linear XL columns(Polymer Standards Service) with a guard column (PFG PSS) were appliedat a temperature of 40° C. The detection was performed with adifferential refractive index detector. The sample solutions wereprepared with a concentration of 5 mg solids in 2 ml HFIP (+0.2M KTFA),and the samples were dissolved for a period of 24 hours. Calibration isperformed with eleven polymethyl methacrylate standards (polymerstandard services), ranging from 500 to 2,000,000 g/mol. The calculationwas performed with Empower Pro software (Waters) with a third ordercalibration curve. The molar mass distribution is obtained viaconventional calibration and the molar masses are polymethylmethacrylate equivalent molar masses (g/mol).

Standard Conditions

As used herein, unless the context indicates otherwise, standardconditions (e.g. for drying a film) means a relative humidity of 50%±5%,ambient temperature (which denotes herein a temperature of 23° C.±2°)and an air flow of (less than or equal to) 0.1 m/s and atmosphericpressure.

The following examples are provided to further illustrate the processesand compositions of the present invention. These examples areillustrative only and are not intended to limit the scope of theinvention in any way. Unless otherwise specified all parts, percentages,and ratios are on a weight basis. The prefix C before an exampleindicates that it is comparative.

Various registered trademarks, other designations and/or abbreviationsare used herein to denote some of ingredients used to prepare polymersand compositions of the invention. These are identified below bychemical name and/or trade-name and optionally their manufacturer orsupplier from whom they are available commercially. However where achemical name and/or supplier of a material described herein is notgiven it may easily be found for example in reference literature wellknown to those skilled in the art: such as: ‘McCutcheon's Emulsifiersand Detergents’, Rock Road, Glen Rock, N.J. 07452-1700, USA, 1997 and/orHawley's Condensed Chemical Dictionary (14th Edition) by Lewis, RichardJ., Sr.; John Wiley & Sons.

In the examples the following abbreviations/monomers may be used:

DBI denotes dibutyl itaconate (may be (partly) bio-renewable)DEI denotes diethyl itaconate (may be (partly) bio-renewable)DMI denotes dimethyl itaconate (may be (partly) bio-renewable)MMA denotes methyl methacrylate (may be (partly) bio-renewable)BA denotes butyl acrylate (may be (partly) bio-renewable)STY denotes styreneIA denotes itaconic acid (may be bio-renewable)IANH denotes itaconic anhydride (may be bio-renewable)AA denotes acrylic acid (may be bio-renewable)MAA denotes methacrylic acid (may be bio-renewable)AIBN denotes azobisisobutyronitrileDTPO denotes di-tertiairy butyl peroxidePEG350 denotes the methoxy polyethylene glycol methacrylate availablecommercially from Cognis (part of BASF) under the trade mark Bisomer®mPEG350MA.

EXAMPLE I

To a round-bottomed flask equipped with a condenser, thermometer, and astirrer are charged 43 parts of 2-butanone. The reactor contents areheated to 85° C. As soon as the polymerization temperature is reached, amonomer feed consisting of 25 parts of dimethyl itaconate (DMI), 20parts of styrene (STY), 25 parts of methyl methacrylate (MMA), 30 partsof acrylic acid (AA), and 0.3 parts of azobisisobutyronitrile (AIBN) isfed to the reactor in a period of 270 minutes. At the end of the monomerfeed the polymerization temperature is kept at 85° C. for another 60minutes after which the reactor contents are cooled back to roomtemperature.

EXAMPLES II TO X

The Examples II to X are prepared analogously with reference to themethod described in Example I above with reference to Table 1 belowwhere the monomer feed in Example I is replaced with those ingredientand in the relative amounts listed in the Table 1.

TABLE 1 II III IV V VI VII VIII IX X DMI 25 62 55 43 61 55 55 55 55 STY—  5 — — —  5 — — — MMA 25  3 15 32  9 15 15 20 15 DEI 25 — — — — — — —— AA — 30 — — 30 — 30 — 30 iANH 25 — — 25 — 25 — 25 — MAA — — 30 — — — —— — AIBN   0.8   0.2   0.6   1.0   0.2   1.2   0.2   0.5   0.2

EXAMPLE XI

To a high pressure polymerization kid, equipped with a stirrer,thermometer, pressure release valve, and high pressure monomer dosagepump are charged 43 parts of 2-butanone. The reactor contents are heatedto 140° C. As soon as the polymerization temperature is reached, amonomer feed consisting of 25 parts of dimethyl itaconate (DMI), 20parts of styrene (STY), 25 parts of methyl methacrylate (MMA), 30 partsof acrylic acid (AA), and 0.15 parts of di-t-butyl peroxide (DTPO) isfed to the reactor in a period of 270 minutes. At the end of the monomerfeed the polymerization temperature is kept at 85° C. for another 60minutes after which the reactor contents are cooled back to roomtemperature.

EXAMPLES XII TO XX

The Examples XII to XX may be prepared analogously with reference to themethod described in Example XI above with reference to Table 2 belowwhere the monomer feed in Example XI is replaced with those ingredientand in the relative amounts listed in the Table 2.

TABLE 2 XII XIII XIV XV XVI XVII XVIII XIX XX DMI 25 62 55 43 61 55 5555 55 STY —  5 — — —  5 — — — MMA 25  3 15 32  9 15 15 20 15 DEI 25 — —— — — — — — AA — 30 — — 30 — 30 — 30 iANH 25 — — 25 — 25 — 25 — MAA — —30 — — — — — — DTPO   0.2   0.4   0.1   0.5   0.1   0.1   0.5   0.1  0.1

EXAMPLE XXI

To a high pressure polymerization equipment, equipped with a stirrer,thermometer, pressure release valve, and high pressure monomer dosagepump are charged 34 parts of 2-butanone and 9 parts of 2-ethylhexylalcohol. The reactor contents are heated to 140° C. As soon as thepolymerization temperature is reached, a monomer feed consisting of 25parts of dimethyl itaconate (DMI), 20 parts of styrene (STY), 25 partsof methyl methacrylate (MMA), 30 parts of acrylic acid (AA), and 0.15parts of di-t-butyl peroxide (DTPO) is fed to the reactor in a period of270 minutes. At the end of the monomer feed the polymerizationtemperature is kept at 85° C. for another 60 minutes after which thereactor contents are cooled back to room temperature.

EXAMPLES XXII TO XXX

The Examples XXII to XXX may be prepared analogously with reference tothe method described in Example XXII above with reference to Table 3below where the monomer feed in Example XXX is replaced with thoseingredient and in the relative amounts listed in the Table 3.

TABLE 3 XXII XXIII XXIV XXV XXVI XXVII XXVIII XXIX XXX DMI 25 62 55 4361 55 55 55 55 STY —  5 — — —  5 — — — MMA 25  3 15 32  9 15 15 20 15DEI 25 — — — — — — — — AA — 30 — — 30 — 30 — 30 iANH 25 — — 25 — 25 — 25— MAA — — 30 — — — — — — DTPO   0.2   0.4   0.1   0.5   0.1   0.1   0.5  0.1   0.1

EXAMPLES XXXI TO XXXVI

The Examples XXXI to XXXVI may be prepared analogously with reference tothe methods described herein above with reference to Table 4 below wherethe monomer feed may consists of the ingredients and the relativeamounts listed in Table 4.

TABLE 4 XXXI XXXII XXXIII XXXIV XXXV XXXVI DMI 55 55 55 30 30 30 DBI — —20 MMA — — — 60 60 60 AA 15 15 15 10 DAAM 10 10 10 — — — BA — 20 — — — —IA — — — — 10 — IANH — — — — — 10 PEG350 20 — — — — — Tg (° C.)   37.2  49.4   74.0  101.8  105.9  104.1

EXAMPLES XXXVII TO XLIV

The following Examples XXXVII to XLIV were prepared as described belowand some of their properties results are given in Table 5.

EXAMPLE XXXVII MMA/DMI/AA

To a round-bottomed flask equipped with a condenser, thermometer, and astirrer are charged 394.0 parts of 2-butanone. The reactor contents areheated to 80° C. As soon as the polymerization temperature is reached,13.3 parts of azobis(2-methyl butyronitrile) are added and the monomerfeed and catalyst feed are started. The monomer feed consists of 244.4parts of methyl methacrylate, 244.4 parts of dimethyl itaconate, and244.4 parts of acrylic acid. The catalyst feed consists of 31.1 parts ofazobis(2-methyl butyronitrile) dissolved in 125.9 parts of 2-butanone.Both feeds are added over a period of 180 minutes.

At the end of the feeds 2.5 parts of azobis(2-methyl butyronitrile) areadded and the mixture is stirred at 80° C. for another 150 minutes. Themixture is cooled to room temperature.

To 615.8 parts of the polymer solution is added a mixture of 99.6 partsof a 25 wt-% of ammonia in water, and 1080.5 parts of water. Next, the2-butanone is removed at 50° C. under reduced pressure. The solidscontent is corrected to 22.5% using demineralized water and the pH iscorrected to 8.6-8.8 using a 25 wt-% solution of ammonia in water.

The final polymer solution has a solids content of 22.5% and a pH of8.7.

EXAMPLE XXXVII S/DMI/AA

To a round-bottomed flask equipped with a condenser, thermometer, and astirrer are charged 394.0 parts of 2-butanone. The reactor contents areheated to 80° C. As soon as the polymerization temperature is reached,13.3 parts of azobis(2-methyl butyronitrile) are added and the monomerfeed and catalyst feed are started. The monomer feed consists of 244.4parts of styrene, 244.4 parts of dimethyl itaconate, and 244.4 parts ofacrylic acid. The catalyst feed consists of 31.1 parts ofazobis(2-methyl butyronitrile) dissolved in 125.9 parts of 2-butanone.Both feeds are added over a period of 180 minutes.

At the end of the feeds 2.5 parts of azobis(2-methyl butyronitrile) areadded and the mixture is stirred at 80° C. for another 150 minutes. Themixture is cooled to room temperature.

To 546.1 parts of polymer solution is added a mixture of 105.4 parts ofa 25 wt-% of ammonia in water, and 1144.1 parts of water. Next, the2-butanone is removed at 50° C. under reduced pressure. The solidscontent is corrected to 22.5% using demineralized water and the pH iscorrected to 8.6-8.8 using a 25 wt-% solution of ammonia in water.

The final polymer solution has a solids content of 22.4% and a pH of8.6.

EXAMPLE XXXIX MMA/DMI/AA

To a high pressure reactor equipped with a thermometer, and a stirrerare charged 500.0 parts of 2-butanone. The reactor contents are heatedto 140° C. As soon as the polymerization temperature is reached, 2.9parts of di-t-butyl peroxide and 40 parts of 2-butanone are added. 5minutes later the monomer feed is started. The monomer feed consists of331.8 parts of methyl methacrylate, 331.8 parts of dimethyl itaconate,331.8 parts of acrylic acid, 5.7 parts of di-t-butyl peroxide, and 6.6parts of t-butyl perbenzoate, and is added over a period of 180 minutesat 140° C.

At the end of the feed the feed tank is rinsed with 90.9 parts of2-butanone. 45 minutes after completion of the monomer feed 2.5 parts oft-butyl perbenzoate dissolved in 40 parts of 2-butanone are added andthe mixture is stirred at 140° C. for another 45 minutes. Next, 2.5parts of t-butyl perbenzoate dissolved in 40 parts of 2-butanone areadded and the mixture is stirred for another 135 minutes at 140° C.

The mixture is cooled to room temperature.

To 619.3 parts of the polymer solution is added a mixture of 99.3 partsof a 25 wt-% of ammonia in water, and 1077.3 parts of water. Next, the2-butanone is removed at 50° C. under reduced pressure. The solidscontent is corrected to 22.5% using demineralized water and the pH iscorrected to 8.6-8.8 using a 25 wt-% solution of ammonia in water.

The final polymer solution has a solids content of 22.5% and a pH of8.6.

EXAMPLE XL S/DMI/AA

To a high pressure reactor equipped with a thermometer, and a stirrerare charged 500.0 parts of 2-butanone. The reactor contents are heatedto 140° C. As soon as the polymerization temperature is reached, 4.4parts of di-t-butyl peroxide and 40 parts of 2-butanone are added. 5minutes later the monomer feed is started. The monomer feed consists of331.8 parts of styrene, 331.8 parts of dimethyl itaconate, 331.8 partsof acrylic acid, 8.6 parts of di-t-butyl peroxide, and 10.0 parts oft-butyl perbenzoate, and is added over a period of 180 minutes at 140°C.

At the end of the feed the feed tank is rinsed with 90.9 parts of2-butanone. 45 minutes after completion of the monomer feed 2.5 parts oft-butyl perbenzoate dissolved in 40 parts of 2-butanone are added andthe mixture is stirred at 140° C. for another 45 minutes. Next, 2.5parts of t-butyl perbenzoate dissolved in 40 parts of 2-butanone areadded and the mixture is stirred for another 135 minutes at 140° C. Themixture is cooled to room temperature.

To 617.8 parts of the polymer solution is added a mixture of 99.4 partsof a 25 wt-% of ammonia in water, and 1078.6 parts of water. Next, the2-butanone is removed at 50° C. under reduced pressure. The solidscontent is corrected to 22.5% using demineralized water and the pH iscorrected to 8.6-8.8 using a 25 wt-% solution of ammonia in water.

The final polymer solution has a solids content of 22.5% and a pH of8.7.

EXAMPLE XLI Sequential Polymerization Using the Polymer from ExampleXXXVII

To a round-bottomed flask equipped with a condenser, thermometer, and astirrer are charged 128.9 parts of the alkaline solution obtained fromExample XXXVII. The mixture is heated to 80° C.±2° C.

As soon as the reaction temperature is reached, a mixture of 0.2 partsof sodium persulphate and 0.4 parts of demineralized water is added.After 5 minutes, the monomer feed, consisting of 43.8 parts of methylmethacrylate and 43.8 parts of butyl acrylate, and the initiator feed,consisting of 10.8 parts of demineralized water and 0.4 parts of sodiumpersulphate (corrected to a pH of 8 using a 25 wt-% ammonia solution)are started. Both feeds should take 120 minutes. At the end of themonomer feed, the feed tank is rinsed with 1.2 parts of water. Afterboth feeds are completed, the batch is stirred at 80° C. for another 30minutes, after which it is cooled to 50° C.

At 50° C., one third of a mixture consisting of 0.1 part of a 70 wt-%solution of t-butyl hydroperoxide is added followed by one third of asolution of 0.1 part of iso-ascorbic acid in 2.9 parts of water. 15minutes later and 30 minutes later similar portions are added and thebatch is stirred at 50° C. for another 15 minutes.

The pH is checked and, if necessary, adjusted to 8.4±0.1 using a 25 wt-%solution of ammonia in water. The batch is cooled to room temperature,after which the solids content is adjusted to 48.5%±1% usingdemineralized water.

EXAMPLE XLII Sequential polymerization using the polymer from ExampleXXXVIII

A polymer was prepared analogous to the method described in Example XLI,using the alkaline solution obtained from Example XXXVIII. The finalemulsion was highly viscous, requiring a dilution to a solids content of35%.

EXAMPLE XLIII Sequential polymerization using the polymer from ExampleXXXIX

A polymer was prepared analogous to the method described in Example XLI,using the alkaline solution obtained from Example XXXIX.

EXAMPLE XLIV Sequential polymerization using the polymer from Example XL

A polymer was prepared analogous to the method described in Example XLI,using the alkaline solution obtained from Example XL.

TABLE 5 Results SC (%) Viscosity (mPa · s) pH Example XLI 47.6 208 8.4Example XLII 34.8 1006 8.4 Example XLIII 48.1 35 8.5 Example XLIV 48.1201 8.4

1. A copolymer having a low molecular weight and high glass transitiontemperature, the copolymer comprising (preferably consisting essentiallyof) moieties obtained and/or obtainable from the following components:(a) at least 20 wt-% of one or more itaconate functional monomer(s) notcontaining acidic groups or precursor acid groups), (b) not more than 40wt-% of an acid functional monomer(s) in an amount sufficient to achievean acid value from 65 to 325 mg KOH per g of solid polymer, (c)optionally not more than 72 wt-% of other monomers not being either (a)or (b); where the weight percentages of monomers (a), (b) and (c) total100% and are calculated as a proportion of the total amount of monomersin the copolymer being 100%; and with the provisos: (I) the copolymerhas a number average molecular weight (M_(e)) of no more than 15kilograms/mole (also referred to herein as tow MW'); and (II) thecopolymer has a glass transition temperature of at least 75° C. (alsoreferred to herein as ‘High TG’), and where either or both of provisos(III) and/or (IV) apply: (III) the copolymer contains less than 40 wt-%vinyl aromatic monomer(s) (also referred to herein as ‘Low VinylAromatic’ or Low-Styrene'); and/or (IV) the copolymer contains less than40 wt-% methacrylate monomer(s) (also referred to herein as ‘Low-MA’).2. A polymer composition as claimed in claim 1, in which component (a)comprises a compound of Formula 1:

where Ra and Rb independently represent any optionally substitutedhydrocarbo moiety (such as any aliphatic, cycloaliphatic or aromaticmoieties); and X and Y independently represent —O— and/or —NRc-, whereRc independently in each case represents H and/or any optionallysubstituted hydrocarbo moiety (such as any aliphatic, cycloaliphatic oraromatic moieties) with the proviso that Formula 1 does not contain: anyacidic groups (such as carboxylic, phosphoric and/or sulphonic acidgroups) or any precursor acid groups, that is a group which readilygenerates an acid group under the conditions of polymerisation herein(such as an anhydride group).
 3. A polymer composition as claimed inclaim 1, in which component (b) is an acid functional monomer orprecursor thereof selected form at least one ethylenically unsaturatedcarboxylic acid and/or derivatives thereof (such as anhydrides and/orsalts).
 4. A polymer composition as claimed in claim 3, in which themonomer composition is substantially free of arylalkylene and/or vinylaromatic monomers.
 5. A polymer composition as claimed in claim 1 whichis a solid grade oligomer (SGO).
 6. A process for preparing a polymercomposition as claimed in claim 1 comprising the steps of: (i)polymerising components (a), (b) and (c) (where present) in a solutionpolymerisation process in the presence of solvent, (ii) removal ofsubstantially all the solvent from step (i) to obtain a copolymercomprising at least 95% solids.
 7. A process for preparing a polymercomposition as claimed in claim 1 comprising the step of: polymerisingcomponents (a), (b) and (c) (where present) in a bulk polymerisationprocess, where the bulk polymerisation is performed under at least oneof the conditions (I) (II) and/or (III): (I) in the presence of no morethan 1 wt-% of chain transfer agent; relative to the total monomercomposition (i.e. (a)+(b)+(c)) being 100% (I) in the presence of no morethan 1 mole-% of initiator; relative to the total monomer composition(i.e. (a)+(b)+(c)) being 100%; and/or (III) with a maximumpolymerisation temperature of no more than 250° C., preferably no morethan 200° C.
 8. A polymer composition obtained and/or obtainable by aprocess as claimed in claim
 6. 9. An aqueous composition comprising apolymer composition as claimed claim 1 and an aqueous medium.
 10. Acoating composition comprising a polymer composition as claimed claim 1.11. A substrate and/or article having coated thereon an (optionallycured) coating composition of claim
 10. 12. A method of using a polymercomposition as claimed in claim 1 to prepare a coating composition. 13.A method for preparing a coated substrate and/or article comprising thesteps of applying a coating composition of claim 10 to the substrateand/or article and optionally curing said composition in situ to form acured coating thereon.
 14. A substrate and/or article obtained and/orobtainable by a method of claim 13.